FI ELD OF THE I NVENTION

The present invention relates to protective garments or clothings for the protection against the influence of chemicals .

BACKG ROUND OF THE I NVENTION

There is a great need for protective garments with a low permeability (i . e. a long breakth rough time and a low permeation rate) for certain chemical compounds or mixtures of compounds . The polymer rnem- branes used in protective garments (e. g . gloves, coverall suits, hoods, boots, etc. ) for use in a work environment or in the home must protect against chemical compounds or mixtu res thereof which are hazarduos to the health , such as solvents, paints, varnishes, glues, cleaning agents , degreasing agents, drilling fluids, or epoxy materials . Regarding protective clothing against hazardous chemicals in the work environment or the home, the main concern has previous¬ ly been to obtain chemical resistance of the clothing, i . e. non-degra- dability. During the latest years strong concern about the permeability of protective clothing against chemicals has developed . Permeation studies have surprisingly shown that the breakthrough time is often less than half an hour, sometimes only a few minutes . The studies have also shown that the breakth rough time and the permeation rate is to a g reat extent dependent on the combination of the hazardous substances and the materials for protective clothing . I n view of the foregoing, it is quite obvious that a great need exists for protective garments featu ring polymer membranes without the aforementioned disadvantage. Unfortunately, no other method of selecting suitable combinations than the method of trial and error has been proposed . Epoxy materials and many solvents are particularly important in this context due to their toxic effects and allergenic properties on mamma¬ lian skin, in particular human skin .

SUMMARY OF THE INVENTION

The present invention relates to improved protective garments for protection against chemicals, in particular epoxy materials, and to a rational method of selecting polymer membranes with optimal per ea- tion resistance against hazardous chemicals .

In connection with the research which led to the present invention the applicant has found that commonly used membrane materials (such as polyethylene, various rubbers, neoprene, silicone rubbers, etc. ) have insufficient barrier properties with respect to e. g . epoxy rnate- rials, in that they have breakth rough times of an hour or less . Some of these membrane materials have even been suggested or recommen¬ ded as materials for proctectϊve garments by manufactu rers of epoxy. Applicant has further found that the three-dimensional solubility parameter system pioneered and described by C M. Hansen (cf. ref. 1 , 2, 3 and 4) may suitably be used as a guide for the rational selection of suitable barrier membrane materials for protection garments .

The three solubility parameters termed δ, ,, δ _p and δp. measured in

3 1/2 (cal/c ) , quantify the molecular cohesive forces (the hydrogen bonding, polar and dispersion forces) in a given compound or mixture of compounds. The so far commonly used membrane materials for protective garments have δ, ,- and δ _p -values of about 3 or less, and δ _p .-values of about 9. In view of the low δ, ,- and δ _p -values, these membrane materials are designated as low-energy type polymers be- cause of the relatively low level of intermolecular ^" cohesive forces . These solubility parameter values are fairly close to the solubility parameter values occupied by a major part of the commonly used solvents and epoxy materials .

It has now been found that polymer materials of the high-energy type, i. e. with solubility parameters considerably different from those so far commonly used, exhibit superior properties with regard to being impermeable to chemical compounds, e. g . epoxy materials .

OMPI

The invention relates to a protective garment comprising a membrane comprising a substantially water insoluble polymer material having a solubility parameter set (δ,,, δ _p , δ-.) which is positioned at a solu¬ bility parameter distance of at least 7 from the solubility parameter set (δ _H , δ _p , δ _D ) equal to (0,0,8).

DETAILED DESCRIPTION OF THE INVENTION

The distance A between the solubility parameter set of the chemical ^ ^δ HO' ^δ PQ' ^δ DO-" ^anc * ^{ne s0} * ^u * ^D *'* ^',: y parameter set of the polymer ^HM' PM' n -* ' ^s *-*^' ^1"1 ******-* ^as follows (cf. ref. 1 and 3):

^{A = ((δ} HM- ^δ HO ^)2+(δ PM- ^δ PO ^)2+4(δ D - ^δ DO ^)2)1/2

The parameter set of (0,0,8) is a suitable average representative of a large number of hazardous chemicals encountered in the metal industry, the construction industry, and the chemical industry. While it cannot be said that all hazardous chemicals contribute to this average- (note- able exceptions are e.g. methanol and dimethyl sulfoxide), the haz¬ ardous chemicals which can be said for practical purposes to average at a parameter set of about (0,0,8) comprises by far the major num¬ ber of hazardous organic solvents and plasticizers, polymerization monomers, pesticides and detergents. One particularly important group of hazardous chemicals of which the parameter set of (0,0,8) is representative are the above-mentioned epoxy materials. In the present context, the term "epoxy materials" designates two component types comprising a binder component which contains epoxy monomer, dimer, or trimer, commonly based on diglycidylether of bisphenol A, solvents such as ethylene, butanol, and butylacetat, and optionally pigments and fillers, and a hardener component containing polyaminoamides and optionally aromatic amines or aliphatic polyamines.

In the known art, solubility parameter system is primarily used for formulating paint coatings, i.e., for selecting solvents for particular binders. The principle is that a solvent is selected, the solubility parameter of which is as close as possible to the solubility parameter of the binder. Often, a solvent is selected which is constituted by a

mixture of components , in which case the relevant solubility parameter set is the solubility parameter set of the mixture, which is calculated from the parameter set of the individual components by calculating each parameter in the set as the volume weighted average.

According to the present invention, the solubility parameter set, although calculated in the same manner, is used for a completely different purpose, i . e. , for predicting a completely different combi¬ nation of relative properties between two materials, i . e. , the break¬ through time and the permeation rate of a fluid in a polymer mem- brane: It has been found that the greater the distance is between the solubility parameter set of the fluid and the polymer, the longer is the breakth rough time, and the lower is the permeation rate.

In practice, acceptable results with respect to increased breakth rough time and reduced permeation rate are obtained when the distance between the parameter set of (0,0,8) and the parameter set of the polymer, calculated as described above, is at least 7, preferably at least 9, in particular at least 11 , and most preferred around 13.

Materials which comply with these conditions are the so-called high- energy polymer materials, i . e. , polymer materials with high molecular cohesive forces, in particular high hydrogen-bonding and polar cohe¬ sive forces, while most known polymer membrane materials, including polymer membrane materials conventionally used for protective gar¬ ments, are low-energy polymer materials (which typically are at a distance of 6 or lower from the solubility parameter set of (0,0,8) .

The synthetic polymer high-energy material is one which is substan¬ tially water-insoluble. This term includes materials which will undergo swelling in contact with water, but is intended to exclude materials which are actually soluble in water. An example of a high-energy material which is soluble in water is polyvinyl alcohol . Although polyvinyl alcohol shows a high breakthrough time and a low permeation rate for epoxy materials such as shown in the experimental section, and although polyvinyl alcohol has in fact been suggested as a mem¬ brane for a protective garment, vide German Offenlegungssch rift No.

2330316, the water soluble character of PVA results in a number of disadvantages which are believed to exclude its utility as a protective garment membrane for practical purposes :

The water solubility of PVA renders it subject to dissolution in contact with external aqueous media or in contact with sweat. Furthermore, even small amounts of water or moisture which will not di rectly dis¬ solve a PVA membrane will tend to swell and plasticize the membrane to such an extent that it loses the permeation resistance properties it would otherwise possess in view of its position in the solubility para- meter system. Moreover, in the practical processing of PVA, where large amounts of plasticizer must be used which will tend to increase the mobility of the PVA molecules and hence to increase the permea¬ bility.

A particularly interesting class of polymer materials for the pu rpose of the present invention are copolymers substantially free of plasti- cizers, since the presence of plasticizers increases the mobility of the polymer molecules and hence increases the permeability .

An especially interesting class of polymer materials are copolymers of a C~_ _c alkene substituted with up to 4 hydroxy groups and a C _^ r alkene, or homopolymers of a C« -. alkene substituted with up to 4 hydroxy groups. The C~ ,- alkene is preferably ethylene.

A particularly useful copolymer is a vinyl alcohol-ethylene copolymer.

In the following, the designation "PVAE" is used to designate a vinyl alcohol-ethylene copolymer.

It is preferred that the vinyl alcohol-ethylene copolymer contains 40-80 mole per cent of vinyl alcohof and 20-60 mole per cent of ethy¬ lene. I n particular, it is preferred that the vinyl alcohol-ethylene copolymer contains 65-75 mole per cent of vinyl alcohol and 25-35 mole per cent of ethylene.

O PI

Vinyl alcohol-ethylene copolymers are described, inter alia, in DE Auslegeschrift No. 22339806, GB Patent No. 1212569, GB Patent No. 1247114, and G B Patent No. 1489635. Vinyl alcohol-ethylene copoly¬ mers suited for the purposes of the present invention are produced, e. g. , by Kuraray Company Limited, Osaka, Japan, and are available under the trade name "Ku raray EVAL" . They are normally used as packing materials for food; the main reason for their suitability for this purpose is their resistance against permeation by oxygen and their capability of reducing the loss of aromas from the food .

As appears from the experimental section, the PVAE materials show unique advantages for the pu rpose of the present invention in that they show extremely long breakthrough time. In contrast to PVA, the PVAE materials may be produced and shaped into membranes without the use of plasticizers , but with excellent flexibility and plyability. I n addition to the advantage the the PVAE membranes have an extremely long breakthrough time, they show the advantage of the main com¬ ponent in epoxy materials, DGBEA, does not wet PVAE materials, which is attributed to the fact that PVAE materials have a very high hydrogen binding parameter δ, , compared to DGEBA. This is of major importance in the practical use of the garments according to the invention and contributes to the high barrier effect of the PVAE materials because the contact area between the membrane and the epoxy material is then essentially reduced.

According to particular embodiment of the invention, the substan- tiaily water insoluble high energy polymer material is laminated with a layer of another polymer. Several advantages may be obtainable by laminating a layer of the high energy synthetic polymer used accor¬ ding to the present invention with another polymer such as a poly- olefin, in particular polethylene or polypropylene:

PVAE materials exhibit some absorbtion of water. Water absorption in the PVAE material will to some extent reduce the barrier function of the PVAE membrane due to a certain plasticizing effect of the water. As a protective garment is subject to the influence of water from perspiration, an important type of laminate is one which comprises a

- 3 REAc OMPI

polymer layer of a type which will reduce water permeation, such as polyethylene or polypropylene, for application against the skin . Another possibility is to laminate the other polymer to the outside of the high energy polymer for protection against external water such as rain or spray.

Some chemicals, e. g . amines and alcohols , are able to permeate PVAE rather easily, but are not capable of permeating polyethylene. Thus, a laminate comprising polyethylene and PVAE is an excellent barrier against both chemicals with high δ, , , δ _p solubility parameters and chemicals with low δ, , , δ _p parameters . PVAE/polyethylene laminates, therefore, provide a superior general protecting effect against hazar¬ dous chemicals, including epoxy products . Also, a layer of polyethy¬ lene laminated with a PVAE membrane enhances the mechanical pro¬ perties of the protective membrane and therefere constitute an eco- nomic construction in view of the reletively high cost of PVAE com¬ pared to polyethylene.

I n case of both prolonged wear of the garment or wearing at elevated temperatures as well under conditions subjecting the garment to influence from external water, it will be preferable that the substan- tiaily water-insoluble material having a solubility parameter set posi¬ tioned at solubility parameter distance of at least 7 from the para¬ meter set (0,0,8) constitutes at least one intermediary layer of the laminate, for instance being the central layer in a 3-layer laminate or being layers Nos . 2 and 4 in a 5-layer laminate.

I n such a PE/PVAE/PE laminate, the PVAE layer is effectively pro¬ tected against water, amines , and alcohols . The PE/PVAE/PE laminate in practical dimensions has excellent mechanical properties (flexibility, strength, and elongation) .

The lamination may be performed by extrusion lamination in which the polymer materials are extruded together into one membrane without any aid to help the polymer materials adhere together. Extrusion lamination may also be performed with the use of an adhesive pro¬ moter such as an organometallic titanium compound, e . g . , tetra-n- butyltitanate or tetra-i-propyltitanate. The lamination may also be

OMPI

SsϊdisxS by —tesns of cr-rt Jzing one of the polymers, e.g., oxidizad -5- ^? st lene -film as described in Reference 6. Another method is ^* .δ«*.. a Jon w ^' t an ad e-sjve. In this method, the individual polymer ^s τs are ϊaπ -πaze to sirsr by means of a thin ia _? er (a few microns) ^t . 3/ ■"& ^• * 3 rt$sϊ/β zuch -as -s mod ^" rf*e ^* i 8.5. a modified poly- s ry^πe Or s mc-iϊfe cH ropvle- s uc as th* r/oes R-ar-ufactu ed fey ^ s l Pstrsc etstca ¹ Industry* ^.n-sa y Ltd., Japan, under the ra mai e AD*8£R*< o** i y the ^* VUx»"<b ^* shi Pe -ooheR cat Company Ltd., apas*, uncer the trarfs name MODIC"". Other useful adhasives are O zcrylvc ras ot.5 adhes-v-sε and modified vinylic resinous adhesives,. he -use f -whiah is described in reference 7. This method is espe¬ cially m£$&-ϊ. -if ^' the -polymers have such different cohesive characte¬ ristics that hey do .not adhere well to one another on thei ⁵ "- own, e.g. in the case f a vinyl aisoho! -ethylene copolymer and polyethylene.

5 In order £0 avdtd the pox-sJbϊh ^' ±s- ^* of ptnholes in the high-energy po- Tyrøsr .k&rrΪBr layer of the mem rane, this layer should have a thick¬ ness of .at least .10 TKΠ- irt prsct e, the membrane will usually have a tfrø ness in the -raπcje from shout 25 ym to about 5000 -μm. For dis¬ posable 'Cpa-r eiv . such as cjϊoves, a preferred thickness range is 0 25-20G m particular 50-150 -μ , especially about 100 n . For gartsse-nts for repeated - se, a preferred thickness range is 300-1000 pm, especially 250-500 ro-

The protective -garment of the invention may be a g!ov5 aε mentioned of the disposable type, or of a type for repeated use, a hood for pretectjng the face and head, a boot (both of the disposable type for covering s oes -snd of the rubber boot type), a coverall su ^: t (both of the typ with integral gloves, boots, ar-d hood, n cf the type with -separate c/lcv-es, boots ^ or hood), or an spro-"*.

Fcr Large ggrissrjts su jec e to mechanics! influences such as coverall 0 s its with Iπ e-oral ho d, gloves, and boots, i is preferable that the garmen is also Jamlnated with a reinforcing layer, such aε woven nylcrπ.

BADOftlGINAt , ° ^un

vhe garments or parts of Garments the membrane roa sr*»»t may e heat welded, cast {e. g . by immersion gr dtρ ^» castrng}, pfts ~«*??«i-saiiy extruded, or sown (with subsequent ceve of the

Lsrg-a 3 jits or parts ϋf suits may be lined with e.g. non-woven f'Ssraus material in order to increase mechanical strength and to irtsra ss comfort _*

h inven ion als relates to a method for the ro ec ion of maisrøαlian sfcirt againέi the influence of a chemical or mixture of chemicals... said nethod showing the features set out in any of claims 23-27.

DESCRIPTION Of THE DftA JMGS

fig. ϊ illustrates a protective glove T according to the invention . The - glove is made - from a polyethylene/vinyl alcohol-ethylene copefymer/- poiyethyiene laminate which, for illustration , is shown in a symbolic "deiaminated" fashion . The glove may, e.g. be made from two super¬ imposed layers of laminate by heat sealing along the contour ©f the glove and simultaneously cutting, if desired, the glove may thereafter be turn d inside out so that the seam is on the inside whereby dex¬ terity is enhanced.

Fig. 2 shows a preferred laminate for a garment according to the invention. Reference numeral 2 designates a polyoleofine layer, pre¬ ferably polyethylene or polypropylene, and reference numeral 4 de¬ signates a layer of vinyl alcohol-ethylene copolymer or another suit¬ able high-energy polymer material , Reference numeral 3 designates an * optional adhesive or adhesion promoter. Alternatively, the layers 2 and 4 may be unified by, e. g. , co-extrusion.

fig. 3 illustrates another laminate for use in a garment according to the invention . I n Fig . 3, the numerals 5 and 9 designate the same or different polyoleofines such as polyethylene or polypropylene, and 7 designates a vinyl alcohol-ethylene copolymer. Reference numerals 8

" nE ^ζ i

OMfl BAD ORIGINALΛ. - _WIPO ^'

end 3 designate adhesive or adhesion promoter. Alternatively, the favet-s .-nay be unified fey -ε-S- - so-sxtrusion ,

f , 4 -fltistrates t ^' ^ε relat on -between the distance in solubility pa- rsn-ster (A) and tha time leg breakthroug time - h respect to 5 Me |*rs , ^* s CM- plots o) and ? C (P, plots *) respectively. The in¬ ivi al plots cørr-es- ørtd to the following chemicals : C : CHloroben- zen-e, O- dϊmethyisu!ρhøxide _r v*t -n-hexsne, \z methanoi, T: toluene, Tr: richloroet yiaπe. The curv s gn P reoresent the time lag breakthrough times as a function of the solubility parameter distance

?£* between the polymer and the influencing chemical, it vf l be noted

-that at small distance, the ύtte lag breakthrough time ^' .5 iess than

7000 seconds, whereas consϊ atable im rovements are o tained at distances of 5 and above, in partictiiar at distances at 7 and above.

In the actual case illustrated in Fig . 4, the thickness of the PVC

IS- membrane was 0.7 ram as opposed to 0.5 mm for the Neoprere mem¬ brane. The fact that the PVC-curve is lower than the Neoprene curve - m mrpfise of the greater thick ^* asss of the PVC-rπembraπs reflects in¬ fluence from the high proportion of piasticizer in the PVC -memb ane.

Fig. 3 illustrates the manner in which the time lag breakthrough time 20 Is calculated fn the experimental section . The curve 36 shows the accumulated concentration of the compound in question behind the membrane as the function of the time. At the beginning, the accumu¬ lated concentration ϊs zero and remains zero until the first trace of compound is detected at time T . Thereafter, the accumulated coπ- 25 centration increases and becomes a linear function of time until an equilibrium ϊs reached. The symbol € designates the time lag break¬ through time. This breakthrough time is determined fs- m the extra¬ polations 38 and 40+42 shown in the figure. T is determined at the s actual detection: ϊimtt. T s is therefore different from material to mate-

"0 rial and frøπr experimental setup o experimental setup, which makes comparisons cf the measured results difficult. 8 is dependent of the detection limit in question and is therefore, among other reasons, a better basis for a comparison of membranes .

BAD ORIGINAL

O PI

π

Fig. 6 illustrates a test cell used in the experimental section for monitoring the permeation th rough membranes , an axially extending central inlet bore 14 and, perpendicular thereon, an outlet bore 16. At each end, the central body is provided with screwed-on caps 18 and 20, respectively. The upper cap 18 secures two to oppositely arranged teflon cones 22 with central bore between which the mem¬ brane 24 to be tested is arranged. I n the bores 14 and 16, bushings 26 and 28, respectively are arranged through which capillary tubes 30 and 32, respectively extend.

In operation, a sample 34 of a fluid chemical is arranged on top of the membrane 24. Th rough the capillary tube 30, a cu rrent of helium gas is directed against the lower side of the membrane 24, from where the gas (together with any chemical which has permeated the mem¬ brane) is discharged through the capillary tube 32 for analysis in a mass spectrometer.

Experimental Studies

The breakthrough time of DGEBA in a series of low energy polymer materials and some high energy polymer materials and laminates of low energy materials with high energy materials was determined. From these determinations, the diffusion coefficient was determined by the so-called time lag method, the time lag diffusion coefficient D. being expressed as

I ² , where I is the membrane thickness measu red

10 6x8 in cm, and θ is the time lag breakthrough time in sec.

The basis of the time lag method ϊs that the permeation rate of a substance that is brought into contact with a membrane becomes constant with time. This means that the concentration of the sub- 15 stance in question in a closed (detection) chamber on the desorption side, after a certain transition period, will become linearly increasing. Finally, in the case when the air in the chamber is saturated or when all of the material has been absorbed, the concentration will remain constant, cf. the typical time lag curve in Fig . 5.

20. The measurements were performed with the aid of the test cell shown in Fig. 6, connected to a mass spectrometer. The instrumentation and the general procedure in the performance of the measurements are described in more detail in the literature (ref. 8) .

The "outer" side of the membrane (absorption side) was covered with 25 DGEBA (diglycidyle therof bisphenol A) . It was determined that the membrane was pinhole-free. The permeation of DGEBA was detected by mass spectroscopic analysis with respect to DGEBA vapor on the "instrument side" (desorption side) of the membrane. The permeation was determined on the basis of the intensity of the signal at the mass 30 numbers 77, 91 and 94, the signal/noise ratio being best for these signals .

As the maximum measu rement period, 240 min (4 hours) was chosen since this time interval corresponds to a working morning of un¬ interrupted contact with epoxy products .

During the measurements, the test cell was thermostated at 40° C.

Materials

The content of impurities of the DGEBA used was less than 1% according to liquid ch romatography .

Permeability measu rements were performed on 14 different membranes . Four of these were specially produced. The others were made avail- able as industrial warehouse products or finished experimental pro¬ ducts . The membranes are specified in Table 1 and 1 a . Membranes 1 -10 were studied in an introductory series of tests , Nos. 11 -15 in a concluding series of tests .

Results

The results of the measu rements are summarized in Table 2 and 2a . The time point T for the first traces of DGEBA in the detection chamber was measured directly. The detection limit was 1 picomole/- sec. The uncertainty of the breakth rough time θ is ± .15%. The mem¬ branes studied were placed in the table according to increasing diffusion coefficient.

PVAE-1/PE was tested for permeability from both sides . After 335 min , the DGEBA had still not penetrated from the PE side. At the measurement after 1217 min , the substance had penetrated .

All membranes were kept completely wetted with DGEBA du ring the tests . No membranes swelled to any directly visible degree with the substance.

14

Table 1 Specification of membranes studied

Material no. and type Thickness Form

(mm)

1 Polyethylene (PE) 0.08 Film

2 Polychloroprene (neoprene, CR) 0.54 Plate

3 Silicone rubber (VSi) 1.16 Plate 4 Polyvinyl alcohol (PVA) 0.07 Film

5 Butyl rubber I (PIB, 1IR) 0.22 Plate

6 Butyl rubber II (PIB, MR) 0.48 Glove

7 Natural rubber (NR) 1.1 Plate

8 Polyisoprene (PIP) 1.1 Plate 9 Ethylene-propylene-terpolymer

(EPDM) 0.9 Plate

10 Chlorobutyl rubber/EPDM mixture 1.32 Plate

11 PE/PVAE-1/PE laminate a) 0.056 Film

12 PVAE-1/PE laminate 0.095 Film 13 PVAE-1 0.020 Film

14 PVAE-2 0.016 Film

15

t m

Table la Specification of membranes studied

Material Supplier: no. Product brand

1 Allhabo, Sweden: Alloten LD

2 DuPont, USA:

3 DuPont, USA:

10 4 Kurashiki, Japan: Vinylon

5 Trelleborg, Sweden: 8700

6 Arsima, Arsima: 60951-3

7 Schønning & Arve, Denmark: AT-1

8 Schønning & Arve, Denmark: AT-2 15 9 Codan, Denmark: EPDM EJ-41*

10 Codan, Denmark: Chlorobutyl/EPDM CB-13/

11 Kuraray Co. Ltd. Osaka, Japan: PE/EVAL-E/PE- coextruded film

12 Kuraray Co. Ltd., Osaka, Japan: EVAL-E/PE- 20 lami-film

13 Kuraray Co. Ltd., Osaka, Japan: EVAL-E

14 Kuraray Co. Ltd., Osaka, Japan: EVAL-F

a) Three-layer laminate: polyethylene/vinyl alcohol-ethylene-copoly- 25 mer/polyethylene.

* NR, PIP, EPDM and chlorobutyl rubber/EPDM plates (Nos. 7-10) were especially produced for this study.

16

Table 2 fytsjr" brane πater ^j als, time αf first trace of OGE8 , breakthrough ime, dϊ? usion coefficient and sotabiltty parameters

DGEBA C ^rt epc-< monomer"} Membrane First trace Break- thickness of DGEBA, through

T time for DGEBA, θ

1d emb***as*e no. ^* jnd materials (.fflraj ^' min) (min)

4 ftriyviϊiyl ^alcohoi (PVA) 0.07 >240 >2ώ0

11 PS FVAE-VPE 0.056 >240 >240

12 PVAE-T PE 0.095 >240 >240 t5 13 PVAE-5 0.020 >240 >240

14 FVAE-Ξ 0.016 >240 >240

1 Pøξyethyiene (P£) 0.08 2.0 4.4

5 Sutyl rubber ϊ

CPΪB, II } 0.22 2.5 5.6

20 δ Butyl rubber H

(P B, HR3 0.4S 25 46

2 Polychforcs-β-ie

(neoprene. CH} 0.54 16 38

IS Chlorøbtrt-*i/£PDM 1.32 11 75

25 7 natural r b e (NR) 1.10 7.3 24

8 Poiyis prene (PIP) 1.10 6.5 24

%τ Ethyleneprcpyen-ter- - polymεr CE 'M) 0.90 15

3 SUIcone rub e (VSi) 1.18

30

OMPI

17

Table 2a

Membrane Diffusion Solubility parameters Refe¬ Distance no. coeffici¬ rence between pa¬ ent. rameter set

D _L x10 ⁸ δ _H δ _p δ _D DGEBA/ma- terial, A

( . — /„„„ ^• •, -.-.!/ 3.1/2 (cal/cm )

10 DGEBA 5.51 5.88 9.95 (3)

4 <0.057 13 7 8.5 ^,J 8.1 ^j

11 <0.036 10.5 6.5 8.5 ^1} 5.8 ⁴⁾

12 O.104 10.5 6.5 8.5 ¹⁾ 5.8

15 13 <0.005 10.5 6.5 8.5 5.8

14 <0.003 10.5 6.5 8.5 ¹⁾ 5.8

T 4 ~0 ~0 8.1 (10) 8.9

5 24 2.28 1.23 7.10 (3) 8.07

7.8

6 14 ¹⁹ 1.6 1.1 7.8 (11) 7.58

20. 2 21 1.3 1.5 9.5 (11) 6.2 ² ιo ^' 65 - - - -

7 140 3.5 1.0 9.0 (11) 5.6

5.6 ³⁾

8 140 -0.40 0.69 8.10 (3) 8.8

9 152 1.0 0.4 8.8 (11) 7.5

25 3 197 2.2 1.8 8.0 (11) 6.6

1) The solubility parameters are, as far as is known, not established for PVA and PVAE. The values stated are estimated.

2) Secondary solubility range left out of consideration. 0 3) The solubility parameters for PIP (synthetic natural rubber) were determined with the aid of "raw elastomers" (ref. 3). The solubi-

lity parameters for NR (natural rubber) were determined with res¬ pect to vulcanized material . Since the membranes studied of both PI P and NR consists of vulcanized material, it appears reasonable to use the solubility parameters for NR in the distance calculations with respect to both material types .

Discussion

The membrane thicknesses are of the same order of magnitude as those which occur in safety gloves . The measured breakthrough times

8 and trace times T therefore by themselves give an impression of s the suitability of the material for safety gloves . Several membranes are of essentially the same thickness, which enables direct comparison of θ and T within subgroups of the membrane materials in question . Where there are differences in the membrane thickness, the compari¬ son should be based on the calculated diffusion coefficient.

The breakthrough time θ varied within the group of all membranes studied between 4.4 min (0.08 mm polyethylene (PE)) and more than 240 min (0.07 mm polyvinyl alcohol (PVA) , 0.056 mm PE/PVAE-1/PE and the like) .

Disposable gloves manufactured from PE are, according to experience of the Labor I nspection's Administration of Worker Safety Regulations with Epoxy Products and Use of Them, quite common as a protection against DGEBA and other constituents. In addition, gloves of poly¬ vinyl chloride (PVC), nitrϊle rubber, neoprene or natural rubber are used. The results reported above demonstrate the clear superiority of the PVAE materials over these known art materials.

Regarding laminates, one might fear that PVAE when laminated with PE, because of the "compulsory wetting" via PE, would have a shor¬ ter breakthrough time than non-laminated PVAE. It was found that the breakth rough time of DGEBA in contact with a PVAE/PE laminate was longer than 240 min , regardless of whether DGEBA was brought into contact with the PVAE or PE side of the laminate. The possible compulsory wetting effect is therefore not of essential importance.

OMPI

References Cited t .

1) Hansen, CM. & Beerbower, A: "Solubility parameters, p. 889-910 in Kirk-Othmer: Encycl. Chem. Techn. Suppl. Vol., 2nd Ed., Wiley & Sons, New York 1971

5 2) Hansen, CM.: The three dimensional solubility parameter and solvent diffusion coefficient, Their importance in surface coating formulation, Danish Technical Press, Copenhagen 1967 (106 p.)

3) Hansen, CM.: Solubility in the coatings industry, Farg och Lack, 77(4}, 69-77(1971)

10 4) Hansen, CM.: "The universality of the solubility parameter", Ind. Eng. Chem. Prod. Res. Dev., 1969 (8:1)2-11.

5) DE-Auslegeschrift 2339860

6) GB Patent 1212569

7) GB Patent 1247114

15 8) Klaschka, F.: Physiologische Grundlagen des Hautschutzes, Arbeitsmed. Sozialmed. Praventivmed. , 15(1 ^' ), 2-5 (1980)

9) Linnarson, A. & Halvarson, K. ^* . Studie av polymermaterials genom- slapplighet. for organiske fδreningar (FOA-Rapport C-20414-H2), Fδrsvarets Forskningsanstalt, Stockholm 1981.

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13) GB Patent 1489635

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