The object of the present invention is a FLEXIBLE ULTRAVIOLET RADIATION BLOCKING TEXTIL ASSEMBLY. More specifically, it describes a fabric assembly characterized by the following layers : 1st Layer. 100% cotton fabric 2nd Layer. PVC (PVC laminate) coated cotton substrats.

3rd Lgyer. 100% cotton fabric.

The raw material in question was developed for the manufacture of clothing, hats, gloves and other articles.

Background The ultraviolet protection factor (UPF) is a classification index providing the consumer with information about the relative ability of a product to protect against solar ultraviolet radiation. Depending on the obtained rating, the product can be classified as providing good, very good or excellent protection.

Basically, the factor is obtained by comparing the effect of exposure to the sun of the bare human skin with the effect of exposure to the sun of human skin protected by the product (fabric). To this effect, the standard sensitivity of unprotected skin (E (X)) exposed to standard solar radiation (S (X)) is compared to the filtering effect of standard solar radiation (T (X)) offered by the

fabric. The standard solar radiation used as basis for the solar UV-Index <BR> <BR> <BR> <BR> <BR> corresponds to the solar spectral irradianc measured on January 17, 1990 in Melbourne, Australia. The standard sensitivity of the human skin is given by erythem (redness) induced by ultraviolet radiation, known as erythemal effectivity curve (International Commission on Illumination).

The UPF determines exclusively the degree of protection against solar radiation provided by fabrics in dry and relaxed (not tensioned) state. The solar ultraviolet spectrum considered is UV-B (280 nm to 315 nm) and UV-A (315 nm to 400 nm).

UPF is applicable to protecting fabrics, clothing and other garments worn in near proximity to the skin.

The UPF is not indicated for weighting or classifying protective products used at distance from the skin as for example shade products. The UPF is also not indicated for rating UVR protection provided by sunglasses, for which there are specific norms, or for products directly applied to the skin such as sunscreen lotions, which are indexed by another factor-the sun protection factor (SPF). The UPF is furthermore not indicated for products used in architecture or agriculture as for example blackout blinds and fixed shade systems for greenhouses.

Although the rating is aimed to guide the consumer, there is no direct relation between UPF and SPF, which uses to be known better by the public. As a matter of fact, the two factors are determined through different methods. While the UPF is determined in vitro, the SPF is determined ín vio, that is, using the skin of human volunteers, what makes the

results of SPF rating depend among others on cellular bio-activation phenomena.

Due to these differences it is difficult to correlate these two factors.

State of the Art The patent hIr. Pl9604233-8 A, published on May 26, 1996, describes the production process of a flexible impermeable pellicle, involving the following steps: immersion of a polyester pellicle (1) in dyed PVC solution (2); drying of the textile pellicle (1) drenched with PVC solution (2); thermofixation of the textile pellicle drenched with PVC solution (12) in a translucid PVC film (3).

Patent PCT US 97/14484 published on 18/08/1997 refers to a pre-fabricated flexible multi-layer product to be used for coating outdoor structures or as isolated product. A substrate of textile material is joined in parallel to a synthetic membrane to form a double-layered laminate. A thermoplastic pellicle between the layers accentuates the assembly.

Note : The principal purpose of the above-mentioned inventions is impermeability while the main purpose of the invention here presented is protection against ultraviolet radiation.

Summary : The invention here presented refers to a process for obtaining a flexible multi-layer product with the main characteristic of providing protektion against uliraviolet radiation, composed by:

1st layer: 100% cotton fabric.

2nd er: PVC (PVC laminate) coated cotton substrate 3rd layer : 100% cotton fabric The process involves the following steps: 1 st tayer. 100% cotton fabric.

A pre-fabricated flexible 100% cotton fabric (1St laye'r-cotton fabric) can be used as isolated product. The composition of the fabric should be: weight : 310 to 420g/m2-9 and 12oz/yd2 ; structure 3x1 ; warp 2,5 to 5, weft 1 to 4.

2nd step: 2nd layer. PVC (PVC laminate) coated cotton substrate.

100% cotton fibers, cross-disposed so as to form a substrate for sustaining a mass obtained from PVC granulate, formula : 300g PVC x m2 + 60g mesh = 400g x m2 x 1,40 = 600g PVC per linear meter/1 00m = 60 k (2"d layer-PVC laminate), melted under heat in an extrusion press for obtaining a PVC and cotton mesh density of 2 to 10 micra.

3rd step: 3rd layer. 100% cotton fabric.

The first two layers (1st layer 100% cotton fabric + 2nd layer - PVC laminate with sustaining cotton mesh) are fixed together by spreading the polyurethane and/or f00% acrylate adhesive between the layers of cotton fabric and the PVC

laminate in a hot pesser; both layers are covered simultaneously with the adhesive, cooled, heated again and immediately pressed.

4 step : Pre-fabricated 100% cotton fabric (3rd ls cotton fabric) weighing between 310 and 420g/m2-9 to 12oz/yd2 ; structure 3x1 ; warp 2,5 to 5 and weft 1 to 4. This layer is fixed by means of sewing to the first two layers (cotton fabric and PVC laminate on sustaining cotton mesh) previously glued with 100% polyurethane and/or acrylate.

The cotton fabric layers should have a weight between 310 a 420g/m2-9 a 12oz/yd2 ; structure 3x1 ; warp 2,5 to 5 and weft 1 to 4.

4. 2 Tests performed The following test for measuring spectral transmittance to determine the parameters established by rule AS/NZS 4399: 1996 were performed: - Standard ultraviolet protection factor; -Medium ultraviolet protection factor; - Effective ultraviolet transmittance; - Arithmetic mean of UV-A transmittance; - Arithmetic mean of UV-B transmittance ; All these parameters were obtained for fabrics in dry and relaxed (not tensioned) state; the general procedure used was the same in all cases.

4. 2.1 Parameters established by rule AS/NZS 4399 : 1996 The rule establishes a number of parameters as there are : methodological requirements, instrumental and test conditions and classification of the fabric. These parameters are the following : A Method for the determination of ultraviolet radiation transmission 1. The method used for measuring ultraviolet radiation transmission is total spectroradiometry, that is, direct and diffuse transmission should be measured using an integrating sphere and a source of radiation simulating the solar spectrum. Purpose: measure the total ultraviolet radiation passing directly through the fabric as well as the radiation transmitted by diffusion.

B. Classification of the ultraviolet protection factor 1. The rule establishes the classification of the quality of protection against soiar ultraviolet radiation as follows (table 1) Tabel 1. Classification system for ultraviolet protection factor Category of Protection Effective Transmission of Nominal Ultraviolet UPF against Ultraviolet Ultraviolet Radiation (%) Protection Factor Radiation 15 to 24 Good protection 6,7 a 4,2 15,20 25 to 39 Very good protection 4, 1 a 2, 6 25, 30, 35 40 to 50,50+ Excellent : protection s 2, 5 40, 45, 50, 50+

Arithmetic mean of UV-A and UV-B transmission The arithmetic mean of transmission of UV-A radiation is given by : TUV-V mean = (T315 + T320 + T325 +.....+ T395 + T400)/18 The arithmetic mean of transmission of UV-B radiation is given by : TUV-B mean = (T290 + T295 + T300 + T305 + T310 + T315)/6 Effective Ultraviolet Transmission The mean effective ultraviolet transmission for the fabric exposed to solar radiation is given by : S (S he spectral solar radiation, and T (X), the spectral transmission of the specimen.

Mean Ultraviolet Protection factor

The mean effective ultraviolet radiation for unprotected skin is given by: E (X), the relative erythemal dose for human skin.

The mean effective ultraviolet radiation for skin protected by the fabric is given by:

The ultraviolet protection factor is established by relating the mean effective ultraviolet radiation for unprotected skin with the mean effective ultraviolet radiation for skin protected by the fabric : Eunprotected Protected The mean ultraviolet protection factor is obtained on the basis of the ultraviolet protection factor of N specimens of the fabric sample : llPFmean = (UPF1 + + UPF2 + UPF3 +..... + UPFN)/N (7) The mean ultraviolet protection factor has a standard aeviation : The expanded standard error of UPFmean, calculated for a confidence level of 99% is obtained using the Student's t distribution factor for k= (N-1) degrees of tolerance : Nominal ultraviolet protection factor The nominal ultraviolet protection factor is obtained through the following steps: st step : For greater safety, the nominal UPF is calculated on the basis of the lowest probable UPF values, that is, on the basis of: UPFminimum = (UPFmean - uupf)

For even greater safety, the rule AS/NZS 4399 : 1996 classifies the norminal ultraviolet protection factors only in multiples of five, obtained by rounding the result of the equation (10) to the immediately next inferior multiple of five. This way, for example, a result indicating a minimum ultraviolet protection factor 19 would in fact be classified as 15. To be classified as UPF 20, the a result would have to be equal to or higher than 20. Thus, during this step, the nominal protection factor can be established as follows : UPFnominal = 5. {Rounded to next inferior[(UPFminimum)/5]} (11) Rounded to next inferior is here understood as rounding the result of dividing UPFmjnjmum by five to the next inferior multiple of five.

2step : In case the UPFnominal found in the first step were inferior than the minor individual UPF obtained for the sample (minor UPF ;), then the ultraviolet protection factor has to be obtained by rounding the minor individual UPF to the next inferior multiple of five: UPFnominal = 5. {Rounded to next inferior [(FPU minimum)/5]} This way the rule aims to avoid classifying the nominal UPF on the basis of results with very high standard deviation.

RESULTS The results obtained for the samples of fabric in dry and relaxed state are shown in the tables below. The tables show : the ultraviolet protection factors obtained under the above mentioned conditions for each of the four specimens under test ; the respective mean ultraviolet protection factor ; the standard deviation of the protection factor of the sample ; the standard error of the mean protection factor and the nominal ultraviolet protection factor obtained in step 1 and 2. Furthermore, the tables display the arithmetic means of transmission of ultraviolet radiation A and B and the effective ultraviolet transmission of the sample with standard deviation at a 99% probability level. Mean Ultraviolet Protection Factor of the Samples Black UPF1 UPF2 UPF3 137 IJPF4 ......... Standard Deviation of the Protection Factor of the Samples Black Comosition Standard Error of the Mean Protection Factor-N = ; t = Black Composition White Composition : . : Nominal Black jPJJ SO 35 | ;, ,,,.. , 4. Af. 9L'.

Arithmetic E WMe UAiOJOJ I UVAsOJOJ UVA4OJ0, 1 UVA, 0, , 0, i 0, 1 : 'aP'.', ,, USX Sa. i. i4-''_s xr=r'''-. _'-Y=. '-, r r ^ a , Black ! l1 VB1 UVBZ,, UVBoq UVB3 lJIVB4 0, 9 9 = : : , 9°/m 0, 0 0, 0 Effective Ultraviolet of Samples (%) Black Composition 0, VEfl 0, 09 0, 09 Ef2 LlVEf3 0, 09 Ef4 dz ........ .. s °i Bo, oo 00, 00

Summarizing the results of the means of the four specimens tested: Nominal Ultraviolet Protection Factor and Ultraviolet Transmission (%) Standard condition (dry/relaxed) Fabric UPF UV-AMean UV-BMean UVEfmean Black Composition 50+ 0, 1 0, 9 0, 09 white Composition 50+ 0,1 0,9 0,09

CONCLUSIONS The results obtained for the fabrics in dry and relaxed <ed state allow concluding that, according to rule AS/NZS 4399: 1996, the samples of fabric denominated b composition and white composition belong in the category excellent protection.