The present invention relates to a composition and a method for producing an integral skin foam molded article being a molded article of poly urethane foam w ith a density of 0.2 to 0.8 g/cm ⁵ , having dense skin and minute cells shortly and efficiently by a reactive inj ection molding process.

An integral skin foam molded article obtai ned by th e present invention h as an excellent touch and elasticity, and is used for an automobile interior part such as car armrest, steering wheel, console cover, and change speed lever knob, for a covering material or armrest of a chair as furniture, or for safety goods for children such as chair, caster walker, and a surface material of protective goods for playing tool, holding assembly, or safety bar.

From th e viewp oi nt o f reducing the e vironmental burden in rec ent ye ars , a plant-derived resin obtained fro m a plant resourc e has been d esired i n place of petroleum-derived resins using a petroleum resource as a raw material. Namely, the plant-derived resin is compo s ed of a raw m aterial obtain ed from plants l iving through photosynthesi s while taki ng C02 i n air, and even when C02 is discharged into atmosphere by burning treatment after use, the amount of C02 in atmosphere does not increase as a result.

Biopiasti c products release C02 into atmosphere eventually by being burned or decomposed with microbes, but they are made from plants absorbing the€02, thus, C02 in atmosphere does not increase.

In this way, bioplastics are very beneficial from the viewpoint of carbon neutral, but there is a case that important raw materials as food such as corn and sugar cane are used, therefore, there has recently been arising a problem on the change in balance of supply and demand when food is used as industrial materials.

Japanese translation of PCT publication No, 2002-524627 (Patent document 1) discloses a production technique of urethane foam using soybean oil, rapeseed oil, cottonseed oil, or palm oil. Japanese translation of PCT publication No. 2007-507594 (Patent document 2) discloses a technique for producing soft polyurethane by an active hydrogen-containing modification of various vegetable oils such as soybean oil, safflower oil, flaxseed oil, corn oil, sunflower oil, olive oil, canola oil, sesame oil, cottonseed oil, palm oil, rapeseed oil, wood oil, fish oil, peanut oil, safflower oil with a high content of oleic acid, soybean oil with a high content of oleic acid, peanut oil with a high content of oleic acid, sunflower oil with a high content of oleic acid, a high-content erucic acid, and rapeseed oil (crambe oil). In recent years, there are rather many inventions that apply plant-derived raw materials to urethane resins.

In this regard, invention using castor oil, which is a crop not competing with food, and having a hydroxyl group in a molecule very favorable for polyurethane forming as a polyol component for a polyurethane resin has a long history.

For example, there are disclosed the methods of using castor oil, in concomitant use of other polyol though, as polyol of a potting agent for electrical insulation in Japanese Unexamined Patent Publication No. 58-93717 (Patent document 3), as polyol of a polyurethane elastomer in Japanese Unexamined Patent Publication No. 62-1335512 (Patent document 4), and as polyol of a two-component resin paint with no solvent in Japanese Unexamined Patent Publication No. 07-165866 (Patent document 5). These are the core of the development based on the point that castor oil is thought as a lipophilic poly ol having a property of fat, and by the combination of other petroleum-derived polvol, a pol urethane resin with excellent water resistance is developed to be used in the above-described applications.

This castor oil has a chemical structure as triglyceride with about 90% of recinoleic acid and about 10% of a long-chain fatty acid free from a hydroxyl group, and has properties as a polyester type polyol with an average molecular weight of about 950, an average functional degree of about 2.7, and a hydroxyl value of 155 to 165 mgKOH/g.

When this castor oil is actually solidified by reacting with isocyanate, as is known from applications to potting materials and paints, it is possible to produce a relatively rigid molded article with hydrophobieity which is a property of castor oil. When assuming that this castor oil is applied to flexible urethane foam, compared with a polyol component which is generally used in base polyol of flexible urethane foam, that is, polyol with an average molecular weight of about 2000 to 8000, an average functional degree of about 2 to 3.0, and a hydroxyl value of 20 to 60 mgKOH/g, the molecular weight is small and degree of crosslink is too high, as a result, the molded article is too rigid and insufficient in elongation, having a tendency of being rough as a whole.

Hence, in the case of applying castor oil to a flexible polyurethane foam field, some measures are taken, for example, in Japanese Unexamined Patent Publication No. 7-206962 (Patent document 6), the use amount of castor oil is limited; and in Japanese Unexamined Patent Publication No.5-163342 (Patent document 7), WO No. 2007-020904 (Patent document 8) and WO No. 2007-020905 (Patent document 9), aikylene oxide is added to a hydroxyl group of castor oil, a molecular weight is increased by applying a polymer of hydroxy fatty acid, further, since a hydroxyl group of castor oil is a secondary hydroxyl group, whose reactivity is thought to be too low, the hydroxyl group is activated by providing the end of alkylene oxide to be added with ethylene oxide into a primary hydroxyl group.

Even if the molecular weight of castor oil is increased by addition of alkylene oxide or lactone derived from petroleum to synthesize a castor oil-modified polyol with a hydroxyl value of about 80 mgKOH/g or less, the content of a naturally-derived component in the polyol synthesized at the time would be lowered to 50 weight % or less. The cost required for such modification cannot be neglected as well.

in Japanese Unexamined Patent Publication No. 10-87777 (Patent document 10), castor oil of a naturally-derived component is applied to a urethane resin as it is by a relatively high content. This is an invention for forming a foam polyurethane molded article with a density of 10 g/1 to 1100 g/1 consisting of 1) 50 to 99 weight % of castor oil per 100 weight % of polyol component (A), 2) an isocyanate reactive component including 0.9 to 49.9 weight % of hydroxyl groups per 100 weight % of component (A), 3) 0.1 to 5 weight % of water per 100 weight % of component (A), and if necessary, 4) additives, and isocyanate component (B). The examples therein demonstrate that a molded article with a density of 0.055 g/cni3 to 0.15 g/cni3 is foamed uniformly and formed in 22 seconds to 15 minutes, while it shows the reactivity exhibiting a viscosity increase.

In this occasion, as polyol in concomitant use with castor oil, in paragraph 0011, "for example, a compound having a molecular weight in the range of 1800 to 12,000, preferably 3000 to 7000 is listed. The compound must further contain a group capable of reacting with an isocyanate group, and has an (average) functional value exceeding about 2.5, preferably of 2.6 to 3.0, and most preferably of 2.8 to 3.0," and glycol such as diethylene glycol is used as a cross-linking agent. Invention of Patent document 10 shows that in the case of forming by foam molding using water from a polyol component including castor oil by a quite high content, it is possible to foam in a density of the certain level or less, showing a probability of solidification at a relatively low temperature (25°C), but it does not explain about a raw material composition or forming condition for producing an integral skin foam which is a molded article with a density of 0.2 to 0.8 g/cm3 having dense skin shortly and efficiently by a reactive injection molding process.

In particular, a hydroxy! group of castor oil is a secondary hydroxy! group, and a molding time of a polyurethane molded article formed from polyol having a secondary hydroxyl group whose reactivity is relatively low is generally thought to become relatively long, and there is no discussion on productivity improvement at ail.

The present invention relates to a method for producing an integral skin foam, using castor oil and/or castor oil derivative as a naturally-derived component, which includes the castor oil components as much as possible in formulation and has dense skin with an average density of 0.2 to 0.8 g/cm ^J shortly and efficiently by a reactive injection molding process.

Producing shortly and efficiently by a reactive injection molding process means that the time lapse between charging a raw material and starting to open a mold for taking out a molded article (called as a demolding time) is within 3 minutes, more desirably within 2 minutes, and further desirably within 100 seconds.

The major product targeted by the present invention is an integral skin foam having dense skin, and based on classification of polyurethane, semi-rigid urethane foam harder than soft urethane foam, having both shape retention to a certain degree and recovery to deformation, that is, properties as so-called pads.

In general, formulation of a poiyol mixture for producing this semi-rigid urethane foam is designed by the combination of polyether poiyol for flexible urethane foam of ambient temperature curing type (also called as cold curing) of high molecular weight with a cross-linking agent, and it aims at developing a foamed product which is harder and higher in density than flexible urethane foam. The present invention has been studied on the basis of such technical presumption and thought that in this field, castor oil or a castor oil derivative having a hydroxy 1 group in the molecule, a lower molecular weight and a higher degree of crosslink than polyether poiyol for flexible urethane foam, is probably used more efficiently and in the higher content.

The present invention aims to provide a raw material composition capable of producing an integral skin foam having high productivity and maintaining the applicability of a plant-derived castor oil and/or castor oil derivative as high as 40 weight % or more in poiyol mixture.

The present invention relates to a composition for producing a polyurethane elastic foam having dense skin with an average density of 0.2 to 0.8 g/'em3, more desirably

0.3 to 0.7 g/cm3, further desirably 0.3 to 0.5 g/cm3 by a reactive injection molding process from poiyisocvanate (A) and a poiyol mixture (B) consisting of poiyol, a catalyst, a cross-linking agent, a foaming agent, and if necessary, a colorant and other auxiliaries, and in this case, the present invention finds out a condition that castor oil and castor oil derivatives as a naturally-derived component can be included in raw materials as much as possible in the material formulation. The present invention is to provide a composition for a polyurethane integral skin foam, which is a composition for producing an integral skin foam with a density of 0.2 to 0.8 g/cm3 by a reactive injection molding process from polyisocyanate (A) and a polyol mixture (B) including poiyoi, a cross-linking agent, a foaming agent, and a catalyst, wherein

(1) the poiyoi contains 40 parts by weight or more of poiyoi derived from castor oil relative to 100 parts by weight of poiyoi, and the polyol derived from castor oil has an average number of functional groups of 2.0 to 2.7 and a hydroxyl value of 30 to 170 mgKOH/g, and (2) the catalyst contains both tertiary amine and metal catalyst.

According to the present invention, a large amount of castor oil can be used as a polyol component for a polyurethane resin, a polyurethane molded article can he formed in a short time, and the polyurethane resin obtained has good characteristics like abrasion resistance for example.

Fig. 1 is a diagram showing a device to be used in an abrasion resistance test.

As polyisocyanate (A) used in the present invention, one ordinarily used for producing polyurethane foam is adopted. As such isocyanate, there are listed an aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate, their modified substances (for example, a modified substance containing a ureihane group, carbodiimide group, aliophanaie group, urea group, biuret group, isocyanurate group, or oxazolidone group), and a mixture of two kinds or more thereof.

As an aromatic polyisocyanate, there are listed 1,3-and/or 1 ,4-phenyiene diisocyanate, 2,4-and/or 2,6-tolylene diisocyanate (TDI), polymeric TDI, 2,4'-and/or 4,4'-diphenylmethane diisocyanate (MDI), polymethylene polypheny! isocyanate (polymeric MDI), polyaryl polyisocyanate (PAPI) and the like.

As an aliphatic polyisocyanate, aliphatic diisocyanates with carbon number of 2 to

18 and the like are listed. Specifically, 1 ,6-hexamethylene diisocyanate, lysine diisocyanate and the like are listed,

As an alicyclic polyisocyanate, alicyclic diisocyanates with carbon number of 4 to 16 and the like are listed. Specifically, isophorone diisocyanate (iPDI),

4,4'-dicyclohexylmetbane diisocyanate, norbornane diisocyanate and the like are listed.

Among the above-described isocyanates, in the present invention where short time demoiding is required, it is preferable that diphenylmethane diisocyanate (hereinafter also referred to as "monomeric MDi") and/or polymethylene poiyphenylene polyisocyanate (also referred to as "polymeric MDI") are contained (by 30 weight % or more of isocyanate, for example, 50 weight % or more), and it is particularly preferable that isocynate is monomeric MDI and/or polymeric MDI. Here in the present specification, polymeric MDI means a mixture composed of a binuclear component which is diphenylmethane diisocyanate and multinuciear component.

Further, for a polyisocyanate compound, monomeric MDI and polymeric MDI each may contain its modified substance. As such modified substance of monomeric MDI, there can be exemplified a modified substance obtainable by a partial modification of monomeric MDI, for example, introduction of urea, biuret, ailophanate, earbodiirnide, isocyanurate and/ or urethane groups.

Polyol mixture (B) is composed of (Bi) polyol, (B2) a catalyst, (B3) a cross-linking agent, (B4) a foaming agent, and (B5) other component.

The polyol contains 40 parts by weight or more of polyol derived from castor oil, more desirably 50 parts by weight or more, and further desirably 60 parts by weight or more relative to 100 parts by weight of polyol.

The castor oil-derived polyol component may be (i) castor oil as it is (namely, natural castor oil not subjected to a process other than purification), (ii) modified castor oil, and a mixture of these. The modified castor oil includes oxidized castor oil, hydrogenated castor oil, partially dehydrated product of castor oil and castor oil-modified polyol, and the castor oil-modified polyol is preferably (iii) low functional castor oil-modified polyol. As an example of the low functional castor

011- modified polyol, there are a partially acylated substance of castor oil, a substance obtained by condensing castor oil with castor oil fatty acid or

12- hydroxystearic acid, and an ester-exchanged product of castor oil and other natural fat, or polyester type polyol obtained by condensing multifunctional alcohol with castor oil fatty acid or 12-hydroxystearic acid or its condensed substance, and/or a partially dehydrated product of hydrogenated castor oil, its partially acylated substance, an ester-exchanged product of hydrogenated castor oil and other natural fat, or polyester type polyol obtained by condensing multifunctional alcohol with 12-hydroxystearic acid or its condensed substance, and the like.

Further, the castor oil-derived polyol listed above has a component derived from natural castor oil as a major component, and contains a component derived from vegetable oil by 80 weigh % or more of the whole. Namely, the rate of content of a petroleum-derived component in the castor oil-derived poly oi is less than 20% . Even in the case that polyoi contains a castor oil-derived component, when the castor oil-derived component contained in the polyoi is less than 80 weight %, the polyoi is not included in the castor oil-derived polyoi component.

The castor oil-deriv ed p olyoi c omponent ha s an av erage number of functional groups of 2.0 to 2.7 and an average hydroxy! value of 30 to 1 70 mgKOH/g, more desirably an average number of functional groups of 2.2 t o 2.70 and an average hydroxyl value of 100 to 160 mgKOH/g.

Here, polyether polyoi other than plant-derived polyeth er polyoi (particularly, castor oil-derived polyoi), particularly, petroleum-derived polyether polyoi does not exceed 60 parts by weight, for example, 50 parts by weight, particularly 40 parts by weight relative to 100 parts by weight of polyoi (B l ), and may be a mixture of two kinds or more, and it is desirable that an average number of functional groups is 1.5 to 2.5, a hydroxyl value is 20 mgKOH/g to 56 mgKOH/g, and the content of terminal oxyethylene units is 10 to 25 weight % (relative to polyether polyoi).

It is also possible to concomitantly use the so-called polymer polyoi that a polymer obtained by polymerizing an ethylenically unsaturated monomer in polyoi under the presence of a radical polymerization initiator is stably dispersed in polyoi.

As is shown in Example, the inventors carried out forming tests by using 30 to 80 weight % of purified castor oil in 100 weight % of a polyoi mixture which consists of purified castor oil not subj ected to any modification process and long-chain polyether polyoi using a typical semi-rigid polyurethane integral skin formulation, as a result, they have confirmed that a molded article can be taken out w ithout damage by opening the mo id in about 90 seconds with a mo ld s et usually at a temperature of 50°C to 70°C by adjusting to 10 seconds or less of cream time and 30 seconds or less of rise time, which is general forming condition in reactive inj ection molding, nevertheless, a hydroxyl group of the so-called recinoleic acid part in castor oil is not a primary hydroxy! group that is generally explained to be suitable for isocyanate at ambient temperature but a secondary hydroxy! group. As a matter of course, purified castor oi! is superior in cost competitiveness to modified castor oil, on application of vegetable oil to this field, application of purified castor oil is advantageous when a cost-conscious approach is to be taken. On the other hand, in the case where the appl ication rate of vegetabl e o il is tried to increase as much as possible, it has been confirmed that by choosing castor oil-derived polyol effectively, most of petroleu m-derived polyol components can be replaced w ith plant-derived one. The above is the gist of the present invention.

It has been found out that a molded article formed from polyol containing a castor oil-derived polyol component clearly shows better abrasion resistance than that from the conventional polyether polyol in an abrasi on resistance test using sailcl oth shown in Example. In order to exhibit th e ex cel lent abrasion resi stance, it is desirabl e that a compone nt ex ceeding 30 weight %, for ex ampl e, 40 we ight %, particularly 50 weight % of the polyol is derived from castor oii.

This indicates that castor oil-derived polyol is very suitable for an application to the integral skin field targeted by the present invention.

At the same time, Example also shows an average functional degree and a hydroxyl value of the whole base polyol component in the formulation evaluated. As far as this result is studied, seen not only from the functional degree and hydroxyl value of the foregoing castor oil-derived component but also from the average of the whole base polyol including a petroleum-derived component, in comparison with the technical trend of the conventional petroleum-derived polyol, it has become clear that there is a tendency where the functional degree is lower and the hydroxy! value is high as a whole. In regard to the average functional degree and hvdroxyl value of the whole base polyol component in the formulation including a castor oil-derived component, it is preferable that the average number of functional groups is 2.0 to 2.70, and the hydroxy! value is 50 to 170 mgKOH/g, and more desirably the average number of functional groups is 2.2 to 2.70, and the average hydroxy! value is 100 to 160 mgKOH/g. The higher the hydroxy! value (for example, 120 to 170 mgKOH/g), there is a tendency of being excellent in elasticity and recovery from deformation of a molded article.

A cross-linking agent or chain extender may contain poiyhydric alcohol with a molecular weight of 62 to 300, or a low molecular polyol. For example, there are listed ethylene glycol, propylene glycol, butanediol, hexanediol, neopenty glycol, diethylene glycol, triethy!ene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, aikanol amine such as triethanoiamine and diethanoiamine for instance, and EO or PO adduct thereof, and the like, if needed, there can be used a divalent amine, for example, 2,4-and 2,6-diaminotoluene (including 80/20 parts by weight mixture), 2,4'-and 4,4'-diaminodiphenylmethane, polypheny! polymethy!ene poly a mine obtai ed by condensatio of a iline and for aldehyde, diethyltoluenediamine, t-butyltoluenediamine, diethyldiaminobenzene, triethy!diaminobenzene, tetraethy Idiaminodiphen lmethane and the like, and polyether polyol, for example, that alkylene oxide is added to these are also used.

These low molecular po!yo!s/amines can be used alone or concomitantly. The one desirable in the present invention is a difunctional cross-linking agent, and a preferable aromatic polyamine is one that the ortho position of an amino group is substituted by an alky! group, such as l-methyl-3,5-diethyl-2,4-diaminobenzene and/or l-methyl-3,5-diethyl-2,6-diaminobenzene. The amount of a cross-linking agent may be 2 to 10 parts by weight, for example, 3 to 8 parts by weight relative to 100 parts by weight of poiyoi (Bl). When it is less than 2 parts by weight, the amount of poiyisocyanate to react with a polyol mixture becomes small, poor mixing tends to occur, which is unsuitable sometimes. When more than 8 parts by weight, because the viscosity increase by reaction becomes fast, flowability of a mixed liquid becomes bad, it is not practical sometimes.

In the production method of the present invention, water and/or other foaming agent if needed (for example, formic acid) is used as a foaming agent.

The amount of water used as a foaming agent is preferably 0.20 to 0.60 parts by weight, and more preferably 0.25 to 0.50 parts by weight relative to 100 parts by weight of polyol (Bl). When the use amount of water is less than 0.20 parts by weight, liquid fluidity inside a mold deteriorates, thereby sometimes causing the density difference in a molded article to become large. When more than 0.60 parts by weight, because the amount of generated gas becomes large, swell occurs in a molded article, thereby sometimes causing a lot of voids to occur. When the use amount of water is 0.20 to 0.60 parts by weight, regardless of the composition of (A) and (B), a good integral skin foam can be obtained. Additionally, in the above and below, part means part by weight.

As a foaming agent, using water is preferable, while as need, other foaming agent may further be used, and as other foaming agent, there are listed amine carbonate that carbon dioxide is added to an amine compound, formic acid, liquefied carbon dioxide, liquid hydrocarbons, carbonate with crystallization water, other organic carboxylic acid and/or organic carboxylic acid ester and the like. Carbon dioxide (for example, liquefied carbon dioxide) is dissolved in poiyisocyanate and/or a polyol mixture, and this can be used as a foaming agent. For dissolving carbon dioxide, it may be stored under a carbon dioxide gas pressure of 1 to 5 kg/cm2, for example, 2 to 5 kg/cm2 for 2 to 50 hours, for example, 5 to 20 hours while raw materials are stirred.

The above-described formic acid can be used as a main foaming agent.

In this case, the foaming agent is 0.4 to 2.0 parts by weight of formic acid, more desirably 0.4 to 1 .5 parts by weight, and further desirably 0.4 to 1 .0 parts by weight relative to 100 parts by weight of poiyoi (B l ). When formic acid is less than 0.4 parts by weight, foam ing becomes insufficient sometimes, and when more than 2.0 parts by weight, reactivity of a poiyoi mixture becomes low, and foam after demolding swells sometimes.

As far as the cross-section of a molded article is observed, regarding a molded article foamed with formic acid, not only dense skin as more articulate integral skin is formed, but also the demolding time can be shortened because the liquid flows by less foaming gas due to a good fluidity of reaction liquid. However, there i s a possibil ity that water/moisture enters according to a handl ing situation of poiyoi. Form ic acid is easily handled when it co ntai n s about 10 weight % of w ater, thus getting mixed in with water cannot be denied, but the amount of water is desirably 0.2 weight % or less of a poiyoi mixture.

For molding an integral skin foam by a reactive inj ection molding process, there are used a reactive inj ection molding machine such as a high-pressure polyurethane forming machine for RIM manufactured by CANNON Corporation, a high-pressure foaming machine manufactured by Hennecke GmbH, and a high-pressure foaming machine for R-RIM manufactured by Polyurethane Engineering Corporation, and when a large amount of formic acid is used as a foaming agent, there arises a problem of metal corrosion, in particular, to soft iron and structural steel.

In order to extend the life of a forming machine and enhance the stability of raw materials stored in a forming machine, it is preferable that the use amount of tertiary amine used as a catalyst is increased; and alkanoiamines such as monoethanolamine (hereinafter, referred to as MELA), diethanolamine (hereinafter, referred to as DELA), triethanolamine and N-methylethanolamine, weak base containing active hydrogen, such as polyether polyol obtained by adding ethylene oxide and propylene oxide to these alkanoiamines or ethylenediamine, diethylenetriamine, are used as a neutralizing agent.

Because of the increased amount of tertiary amine and use of a neutralizing agent, when a raw material stored in a forming machine, particularly, a polyol mixture including formic acid is set for the pll to be 5 or more, preferably 7 or more, the problem of metal corrosion is solved, and storage stability of a raw material is improved as well as extending the life of a forming machine.

It is essential that the catalyst contains both tertiary amine and metal catalyst.

As an amine catalyst used in the present invention, an aliphatic amine, cyclic amine, ether diamine, hydroxyl group-containing amine and the like are listed.

For example, there are listed a monovalent aliphatic amine (such as N,N-dimethylcyclohexylamine, N,N-dicyclohexylmethylamine, Ν,Ν-dimethylcetylamine, triethylamine, and Ν,Ν-dimethyldodecylamine); a divalent aliphatic amine (such as Ν,Ν,Ν',Ν'-tetramethylethylenediamine, Ν,Ν, ' ,N ' -t etr amethy 1- 1 , 3 -pr opanediamine, Ν,Ν,Ν',Ν'-tetramethylhexanediamine, methylene- bis (dimethy level oh exylamine),

3-dimethylamino-N,N-dimethy l p r o p i o n a m i d e , a d

N.N.N^N ^' -tetraethyimethylenediamine), and an aliphatic amine of 3 to 8 valences or more (such as NV ^N^N ^{^} -pentamethyldiethyienetriamine, N _{^ ^} ^N^N ^{^} -pentame t h y l d i p r o p y l e n e d i a m i n e , a n d N, Ν,Ν',Ν'-t etr a(3 -dimethy iaminopropyljmethanediamine).

As a cyclic amine, for example, there are listed a monovalent cyclic amine (N-methylmorpholine, N-ethylmorpholine, and the like), and a divalent or higher cyclic amine (triethylenediamine, N,N'-dimethylpiperazine, Ν,Ν'-diethylpiperazine, N-methyi-N' -dimethy laminoethoxy pip erazine,

N-(2-dimethylaminoethoxy)morpholine, 1,2-dimethyiimidazole,

1 ,8-diazahicycio[5,4,0jundecene-7) and the like.

As ether diamine, for example, there are listed bis-2-dimethyiaminoethyi ether, 2-(N,N-dimethylamino)ethyl-3-(N,N-dimethylamino)pro p y 1 e t h e r , 4,4'-oxydiethylenedimorpholine, ethylene glycol bis(3-dimethylaminopropyl) ether and the like.

As a hydroxyl group-containing amine, for example, there are listed Ν,Ν-dimethylaminoethanol, EO adduct of Ν,Ν-dimethylaminoethanol, Ν,Ν,Ν',Ν'-tetramethyl-l ,3-diamino-2-propanol,

Ν,Ν,Ν'-trimethyiaminoethylethanolamine,

Ν,Ν,Ν'-trimethylaminopropylethanolamine,

N-methy i-N'- (2 -hydroxyethyl)pip erazine, -(2-hydroxyethyl)morpholine, l-(2-hydroxypropyl)imidazole, 2, 4, 6-tris(dimethylamino ethyl) -phenol, ί ,4-bis(2-hydroxypropyl)-2-ethylpiperazine, and the like.

The use amount of an amine catalyst is preferably 0.4 to 3.0 parts by weight relative to 100 parts by weight of polyol (Bl).

When the use amount of the amine catalyst is less than 0.4 parts by weight, there is a case that unhardened urethane remains on the mold surface in taking out a molded article because surface curing is not sufficient. When more than 3.0 parts by weight, reaction is too fast and liquid fluidity inside the moid deteriorates, thereby sometimes causing the density difference in a molded article to become large. When the use amount is 0,4 to 3.0 parts by weight, by a suitable combination with an organic metal catalyst, it is possible to obtain a good integral skin foam capable of demolding in a short time.

In the present invention containing a large amount of castor oil-derived polyol component, whose hydroxy! group is a secondary hydroxy! group, the organic metal catalyst is an essentia! component. As the organic metal catalyst used in the present invention, there can be listed an organic metal compound catalyst containing the known metal such as tin, antimony, and lead to promote urethane-forming and urea-forming reactions.

For example, there are listed tin octyiate, dibutyltin dilaurate, dimethyltin dilaurate, lead octyiate, iead naphthenate, bismuth octyiate, bismuth neodecanoate, cobalt naphthenate, cobalt octyiate, iron acety!acetone and the like. These organic metal catalysts are used alone or in a mixture. The use amount of the organic metal catalyst is preferably 0.02 to 1.0 parts by weight relative to 100 parts by weight of polyol (Bl).

By changing this amount and sort of catalyst, reactivity of polyisocyanate and a polyol mixture must be adjusted for a time required for completing the reaction rise of foam, a so-called rise time to be 40 seconds or less, for example 10 to 40 seconds.

As other component, a desired additive, reinforcing material or the like can be used.

As the additive, as need, there are used a foam stabilizer, for example, silicone-based foam regulating agent, a surfactant, a weathering stabilizer, for example, antioxidant, UV absorber, a stabilizer, for example, 2,6-di-t-butyi-4-me t h y l p h e n o l a n d tetrakis [methylene- 3 -(3 ',5'-di-t-butyl-4-hydroxyphenyl)propionate] methane, a colorant, an age inhibitor, a flame retardant, a plasticizer, an antifungal agent, a dispersant, a discoloring inhibitor and the like.

The reinforcing material includes glassy, inorganic, or mineral fiber, for example, milled glass fiber and wollastonite fiber, processed mineral fiber or flake, for example, mica and glass flake, and it is used as need. Foam can also be obtained by previously setting glass mat, glass cloth or the like in a mold, then injecting a raw material of polyurethane therein.

The amount of other component may be 200 parts by weight or less, for example, 0,1 to 50 parts by weight relative to 100 parts by weight of polyol (Bl). In the present invention, an isocyanate index [(ratio of equivalent of isocyanate group of polyisocyanate and equivalent of active hydrogen in a polyol mixture)x 100] is preferably 70 to 130 and particularly preferably 90 to 110.

In regard to a molded article produced by the above-described combination, it is often used in a field giving importance to touch, so abrasion resistance is often required in use, thus it is subjected to an abrasion test under the condition shown in Example, and the influence that application of caster oil gives to abrasion resistance of the molded article has been confirmed, As is shown in Example, the application of caster oil showed the tendency to improve abrasion resistance of the molded article.

Hereinafter, the present invention is explained more specifically by means of Examples and Comparative examples. The Examples does not restrict the contents of the present invention at all. In Examples, "part" and "%" are "part by weight" indicate "weight %" unless otherwise specified.

Examples 1 to 7, and Comparative examples 1 to 2

1) In forming, a high-pressure foaming machine of CANNON Corporation was used. The fundamental forming conditions are shown in Table 1.

2) The raw material actually evaluated, the composition and properties thereof are shown in Table 2.

3) The formulation evaluated, forming result and measuring result of physical properties are shown in Table 3. The reactivity indexes of reaction mixed iiciuid in the table are as follows.

Cream time: time (seconds) lapse after mixing a mixture of isocyanate and polyol till the liquid starts rising.

Rise time: time (seconds) lapse after mixing a mixture of isocyanate and polyol till rising of foam is completed.

Additionally, molded articles formed under the condition shown in Table 3 were all formed in 90 seconds and demoided without problems, in either mold 1 or 2.

Physical properties except abrasion resistance were measured after cutting out samples from the molded articles formed in a sheet-like mold of 5.0 mm thick, mold 1,

in regard to an integral skin foam molded article 2, a weight 3 of 1.3 kg is connected to a tip of cotton duck 1 of 45 mm wide (JIS-L-3102 #6) as shown in Fig. 1, the abrasion resistance test of 1000 times is conducted under the condition of stroke: 10 cm and cycle speed: 50 rpm, and appearance of the surface of integral skin foam molded article 2 after test is confirmed with naked eye to determine whether there is a scar or not. OK: one with no scar, x: one with a few scars.

Hereinafter, each result of Examples and Comparative examples is explained briefly. Examples 1 aad 2

In the case where a purified castor oil was used by about 50 to 80 parts of the base polyol part in a polyol mixture, in spite of that the hydroxyl group is a secondary hydroxyl group, they showed a sufficient curing characteristic, which m ade it possible to be demolded in 90 seconds. Fluidity of reaction mixed liquid inside the mold was also sufficient. In spite of that castor oil had a functional group of 2.7 and a hydroxyl value of 160 mgKOH/g, which is a small molecular weight as the base polyol, and a tendency of high degree of crosslink as a whole, they showed an elongation exceeding 100% and tear strength and abrasion resistance which are superior to Comparative examples 1 , 2 where the amount of polyetlier polyol was large.

Examples 3 aad 4

In spite of a low fu nctional degree as explai ned, they showed a sufficient curing characteristic, which made it possible to be demolded in 90 seconds as well. They also showed abrasion resistance superior to Comparative examples.

Examples 5 and 7

Based on the result of Examples 1 to 4, they were evaluated by substituting castor oil and/or castor oil derivative for ail of polyol components referred to as th e so-called base polyol. By adjusting the cross-linking agent and catalyst suitably, no large problems were observed not only in liquid fluidity and curing property, but also in hardness, strength, and elongation of the molded article. This indicates that castor oil and/or castor oil delivative are very suitable for appl ication to th i s semi-rigid integral skin urethane foam field. Examples 6 and 7

By varying the sort of cross-linking agent and changing a foaming agent from water to formic acid, forming was evaluated. No large problems were observed.

Comparative examples 1 and 2

It has been confirmed that when the amount of castor oil-derived component is small, the numerical value of elongation is good, but from evaluation of abrasion resistance, abrasion resistance is superior when the use of castor oil-derived component is large.

Shot time l) ^: Shot time when using Mold 1

Shot time 2): Shot time when using Mold 2 Table 2

Aspect of polyol evaluated

Polyols A and B are a long-chain polyether polyol derived from petroleum, Polyol C is castor oil only subjected to a purification process

Polyol D is ester of castor oil with hydrogenated castor oil fatty acid, and 100% of castor oil-derived component.

Polyol E is ester of petroleum-derived polyhydric alcohol with castor oil fatty acid and other vegetable oil fatty acid, it is composed mainly of castor oil fatty acid, and plant-derived component is 90%.

Table 3

Cross-linking agent '· : l-methyl-3,5-diethyl-2,4-diaminobenzene, and l-methyl-3,5-diethyl-2,6-diaminobenzene

Cross-linking agent ²⁾ : ethylene glycol

Cross-linking agent ^J) : diethanolamine

Catalyst *> : 33% ethylene glycol solution of triethylenediamine

Catalyst ^j) : 70% dipropylene glycol solution of bis-2-dimethylaminoethyl ether

Catalyst ⁶⁾ : dibutyltin dila ate

Formic acid: 99% formic acid (water content 1.0 weight %) Isocyanate: SBU Isocyanate 0632 (manufactured by Sumika Bayer Urethane Co. Ltd., liquid modified MDI (NCO% = 29.0%))

An integral skin foam moided article has an excellent touch and elasticity, and it is used for an automob ile interior part such as car armrest, steeri ng wheel, con sol cover, and change knob, for a covering material or armrest of a chair as furniture, or for safety goods for children such as chair, caster walker, and a surface material of protective goods for playing tool, holding assembly, or safety bar.

Description of number and symbol

1 Cotton duck

2 Integral skin foam molded article

3 Weight