CS204331B1 - Three-layer flat formation capable of absorbtion of the water vapour - Google Patents

Description

The invention relates to a three-layer sheet; and capable of absorbing water vapor consisting of two expanded polyvinyl chloride or vinyl chloride copolymers or mixtures thereof and a textile backing, and a process for producing the same.

Surface formations are continuously produced belts with a thickness of up to 3 mm. They may be single-layer, two-layer, three-layer or multi-layer. They are prepared predominantly by applying plastics or rubbers to various substrates or other combinations. Depending on their composition, these sheets have different physical and chemical properties.

A large part of these flat formations is made of synthetic leather. These are units which serve as a substitute for natural leather and which are comparable with them, especially in terms of hygiene. It is the permeability for water vapor and especially the sorption and desorption of water vapor.

The following methods are known for obtaining the sorption properties of leatherette based on polyvinyl chloride or vinyl chloride copolymer.

The simplest method consists in selecting the textile substrate with hydrophilic properties or impregnating it appropriately with suitable agents, such as vegetable proteins, or some water-soluble polymeric substances, e.g. polyethylene oxides. Such treatments usually have a limited time effect and only occur when water vapor is absorbed from the reverse textile side.

German Patent Specification No. 967,403 discloses synthetic leather of polyvinyl chloride which contains small amounts of high molecular weight water-swellable organic substances in plastisol of polyvinyl chloride in plastisol. Starch, viscose, casein, gelatin, agar-agar, polyamides, cellulose esters and esters are suggested to be suitable. A similar application of these hydrophilic fillers to a mixture of polyvinyl chloride or a mixture of other plastics is disclosed in British Patent No. 5,944,549. No. 1,277,438, U.S. Pat. No. 3,249,465, Swiss patent fi. 353,897 and fis, patent fi. 145 001. Due to the low sorption capacity of the fillers used, only a minimal increase in water vapor sorption was achieved. In the Swiss patent fi. 328 436 and Germany. No. 1,614,960 are incorporated herein by reference. described methods of using polyvinyl alcohol as a hydrophilic substance to achieve surface wettability. polyvinyl chloride based formations.

A disadvantage, however, is that the hydrophilic substance leaches relatively easily from the coating upon contact with liquid water, and when exposed to moisture, the surface becomes sticky, sticky, and unpleasant to the touch. The use of surfactants in a mixture of polyvinylchloride, as disclosed in French Patent No. 5, provides a certain possibility of enhancing the sorption properties. No. 1,432,824; 1,132,594.

Also known are sheets containing crosslinked hydrophilic additives in a mixture of polyvinyl chloride, e.g., sodium polyacrylic acid, crosslinked with epichlorohydrin, which are protected by U.S. Pat. However, the toxicity of epichlorohydrin is defective · Czechoslovak patents fi. 141 625 and 137 947 solve the problem of increasing the wettability by adding collagen fibers. Another fis. patent fi. 136 332 by adding abrasive dust * from synthetic leather. Both methods are of limited significance since they involve the addition of waste materials, the occurrence of which depends on the quantity produced and the method of processing of natural and synthetic leather.

From the German patent no. No. 2,364,628 is a known hydrophilic formation of fiber-forming and film-forming water-insoluble polymers containing modified cellulose ester particles. Polymers include regenerated cellulose (cellulose hydrate), cellulose acetate, alkylcellulose, polyacrylonitrile, polyamides and polyesters. Modified cellulose esters are those whose mere etherification step would result in water-soluble cellulose ethers that are modified to at least largely become water-insoluble but remain water-absorbent. The hydrophilic body has particles of modified cellulose ether uniformly dispersed in the polyraeric mass, or has a surface coated with these particles.

A sheet of polyvinyl chloride or vinyl chloride copolymers is known which is capable of absorbing water vapor with a uniformly incorporated additive of swellable modified polymer which is at least 50% insoluble in water. Modified polymer refers to modified starches of cellulose or cellulose, which are modified by means of thermal energy, radiation or an additional chemical compound which causes crosslinking · The disadvantages of the solution can be seen in the choice of modified polymers used, which are mostly modified natural materials based on cellulosic, starch, casein, etc. The starting materials for the preparation of modified polymers are therefore substances of natural origin, which are currently narrow-profile and for which they are also seeking a suitable substitute in the form of synthetic materials / synthetic starch, synthetic paper other than cellulose etc. /.

A common feature of all the above-mentioned methods for improving sorpine properties is the fact that they have not yet been widely used in mass production, mainly because of a slight increase in sorpine properties with accompanying negative impacts on other properties or a complicated production method.

čs. AO fi. 157 212 and 162 921 disclose a process for the production of thin-walled plastics by various technologies based on the principle that a filler or a mixture of fillers based on water-insoluble macromolecular substances containing polar groups capable of binding water is added to the material to be treated. such as, in the second, a further addition of liquid or mixtures of liquids having a boiling point in the range of 60 ° C to 140 ° C, and a swelling filler in an amount of at least 10% by weight based on the weight of the polymer.

In the above-mentioned production methods, it depends on the amount of filler added e

increase of water vapor sorption. A disadvantage of the production method according to AO 162 921 and 157 212 is the necessity to follow the technological procedure of expansion of the added liquid at 100 to 120 ° C, gelation or further expansion by means of organic blowing agents at temperatures of 170 to 180 ° C. Compliance with this process is unrealistic on the current polyvinyl chloride-based leatherette application lines. Also, the use of a larger amount of the hydrophilic filler according to the above-mentioned AO causes a white refraction in the facing layer, which acts as a visual defect. By the process according to these AOs, non-uniformly lightened structure is achieved in the surface formations, which is caused by the high content of sorbed water in the hydrophilic additive. The present multi-application coating lines do not allow the technological process of expanding the added liquid or sorbed water at 100 to 120 ° C, which is still the state of ungelled plastisol and then without cooling the temperature rise in the next gelatin tunnel to an expansion temperature of 170 to 180 ° C.

The above-mentioned disadvantages of the prior art sheet formulations are overcome by a three-layer ^x flat formation consisting of two lightweight polyvinyl chloride-based layers, vinyl chloride copolymers; optionally mixtures thereof containing plasticizers, stabilizers, blowing agents, catalysts, lubricants, dyes and hydrophilic additives based on cross-linked macromolecular substances and a textile backing, obtainable by simultaneously blowing plastisol of polyvinyl chloride containing 0.3 to 1.0% by weight of 7 azodicarbonamide and 10 to 10 40% by weight of hydrophilic coating additive and plastisol of polyvinyl chloride containing 1.0 to 3.0% by weight of azodicarbonamide and 10 to 70% by weight of hydrophilic additive to base layer, all calculated on the weight of polymer, the hydrophilic additive based on crosslinked macromolecular substances prepared by polymerizing vinylic monomers and containing polar groups capable of binding water such as hydroxyl, amide, and preferably carboxyl groups in H, Na and K forms, contains 0.1 to 2.0% by weight of sorbed water, calculated on the weight of the hydrophilic additive.

The sheet formation according to the invention can be made directly on a textile substrate that remains a part of the article, or on a release liner and subsequent lamination of the textile.

The product has a cover layer with a density of 550 to 900 kg / m and a pore size of 0.05 to 2.0 mm and a base layer with a density of 200 to 550 kg / m and a pore size of above 2.0 mm.

The three-layered sheet according to the invention is characterized by an increased water vapor-absorbing capability compared to known prior art, while at the same time simplifying the manufacturing process. Also other physical, mainly optical properties are at a higher level than similar materials produced so far.

Crosslinked macromolecules are substances which are highly hydrophilic in nature, absorbing relative to the relative humidity of the air during handling of the processes associated with their production, i. for grinding, drying, adjusting, packing, and storing, water vapor. It has been found that water vapor sorbed in this manner in an amount above 2% by weight, based on the weight of the hydrophilic additive, adversely affects the formation of surface deposits when the additive is added to the polyvinyl chloride-based plastisol. In a gelatinous or expanded coating, an inhomogeneous structure is formed under any temperature condition, containing irregular pores of larger dimensions (of the order of several mm) and occurs locally. separating the bearing pad.

The coating is unusable for further application or surface treatment. Only with a sorbed water vapor content of up to 2% by weight, based on the weight of the hydrophilic additive, can we obtain a high-viscosity, high water vapor sorption appearance which is perfect for further use.

For the upholstery of passenger car seats, vehicles and seating furniture, flat formations consisting mainly of two polyvinyl chloride layers and textile knitted fabrics are used predominantly. The classic construction of layers, where the coating is homogeneous and gives the material high resistance to abrasion and mechanical damage, while the lightweight layer allows to achieve lower. % by weight and overall softness, it was also necessary to maintain the hydrophilic additives to achieve the high water vapor sorption of the invention. In order to achieve this increased water vapor sorption from the face of the sheet, the hydrophilic additive must be added in a certain amount, both to the lightweight and topcoat.

The presence of the additive in the topcoat allows the transport of water vapor to the base cellular layer, thereby allowing maximum efficiency of the sorption capacity of the additive. However, the amount of additive added to the topcoat polymer cannot be. arbitrary, since it has been found that when a certain weight ratio of additive to polymer is reached at the point of repeated stress, the color shade, referred to as light refraction, changes.

Since the hydrophilic additive serves as a filler in the polymer blend and is therefore not chemically or physically bonded to the polymer or plasticizer, the additive only has an adhesive bond between its particles and the gelatin polymer.

• Addition of the additive in an amount of 30 to 50% by weight, based on mechanical stress, causes the husk of the additive particles to exert a mechanical stress, which causes color shifts, the so-called light refraction. This achieves relatively low sorption and minimal desorption of water vapor.

% by weight of polymer, polymer layer, additive ratio with the addition of an unfavorable light refraction and more efficient utilization of the additive sorption capacity associated with improved desorption can be achieved by adding an organic blowing agent in an amount of 0.3 to 1.0 wt. cover layer.

The finely lightweight structure of the coating - a density of 550 to 900 kg / m and a pore size of 0.05 to 0.2 mm - does not reduce the resistance of the layer to mechanical damage and abrasion. On the contrary, it enables further increase of water vapor sorption of the whole surface formation.

The base layer having a bulk density of 200-500 kg / m, having a lightweight structure having a pore size above 0.2 mm, gives the whole body not only sufficient water vapor sorption, but also a lower bulk density and overall softness. The density limits resulting from the amount of blowing agent used are given on the one hand by the minimum ability of water vapor sorption, on the other hand by the minimum values of physical - mostly mechanical - parameters of the whole body.

Based on the examples below, which explain the subject matter of the present invention in more detail, the most appropriate ratios and amounts of organic blowing agents and hydrophilic additive used and the most suitable bulk density and pore size of the two polymer layers were determined to satisfy a variety of requirements.

The examples were performed as follows:

1. Preparation of plastisol

Plastisols based on polyvinyl chloride or vinyl chloride copolymers or mixtures thereof were prepared on a high speed mixer at 1000 rpm. These plastisols contained, in addition to conventional additives such as stabilizers, pigments, lubricants, plasticizers, blowing agents and blowing agent decomposition catalysts, the addition of a hydrophilic additive based on the macromolecular compounds which were fed to plastisol in the form of a plasticizer masterbatch.

2. The composition of the mixtures / the amounts of the individual components are given in weight Z, based on the weight of the polymer / and / plastieol for the base layer of an emulsion-containing polyvinyl chloride-K emulsion with 70 phthalate plasticizers of medium gel strength (e.g. dioctyl phthalate (44-54 phthalate plasticizers of good gelling ability) e.g. dibutyl phthalate / 22 - 27 decomposition catalyst of Cd and Zn-based blowing agents 0.5 - 3 azodiocarbonamide-based blowing agents 1-3 pigments 0-20 fillers 0-15 b / plastisol for coating with blowing agent emulsion paste-forming polyvinyl chloride o K «70

plasticizers based on dloctyl phthalate 66-81 blowing agents based on azodicarbonamide 0,1-1 catalyst decomposition of the blowing agent based on Cd and Zn salts 0,5 - 2 pigments • 0-20 fillers 0-10

c / plastisol for coating, blowing agent-free emulsion paste-forming polyvinyl chloride o K with 70 dioctyl phthalate plasticizer organotin heat stabilizer pigments fillers

- 81 0.5 - 2

0-20

0-10

3. Manufacturing Procedures *> 2 a) A 200 g / m plastisol was applied to the paper separation pad for the topcoat with a knife, after its gelation at 160 ° C, it was applied in the same way to a 300 g / m plastisol coating on a white base layer. After gelatinizing the base layer at 160 ° C, an additional 100 g / m @ 2 of plastisol for the base layer was applied with a knife into which the backing fabric of the knitted fabric, the linen fabric and the nonwoven fabric was laminated. The whole assembly was then expanded at 190 ° C and after cooling the sheet was separated from the support.

b / 100 g / m plastisol for the base layer as an anchor coating was applied to the base textile layer of the group of woven or nonwoven textiles, after its gelation at 160 ° C it was applied in the same way to the gelatinized anchor coating 2

300 g / m plastisol for base layer. 2 were then applied to the gelatinous formation

200 g / m plastisol for topcoat. The formation thus prepared was expanded at 190 ° C and temporarily embossed.

Parameters given in the examples to characterize areal formations:

- fat man

- basis weight

- density

- Moisture

- desiccation

- water vapor permeability

- pore size

- Abrasion resistance on Veslic c / Moisture, drying

Moisture is defined as the ability of a material to receive water vapor. The specific toxic is / mg / cm ^ /.

Drying is the ability of a material to release water vapor. The unit of measure is the percentage by weight /% w / w (water vapor permeability

Water vapor permeability is defined as the ability of a material to pass water vapor from a higher relative environment. humidity into the environment with lower relative humidity. moisture. The unit of measure is / mg / cm 2 h 2. The hygienic properties of the surface formations were measured in the 1 - to - reverse direction. e / Abrasion resistance.

Abrasion resistance is defined as the ability of a material or coating to withstand frictional effect under defined conditions (load, sample elongation, etc.).

Mechanical damage to the cover layer is evaluated by steps 1 to 5, with step 5 characterizing the undamaged material, f / pore size

The pore size was focused on an optical microscope at 150 times magnification.

The value given represents the arithmetic mean calculated from two mutually perpendicular dimensions measured for the five largest pores over a 1 cm section.

Examples 1-4

According to the first process and based on the plastisol base layer and plastisol formulations for the topsheet without the blowing agent, surface formations were prepared. Sodium polymethacrylate, crosslinked with 20 Z divinylbenzene, was used as the hydrophilic additive. The hydrophilic additive was mixed with sorbed water. The amount of sorbed water is given in weight X, based on the weight of the additive. The plastisols contained 50 wt. X, based on the weight of the polymer, polymethacrylate Na, A polyester / cotton knit was applied to the backing textile layer. The evaluation is shown in Table X.

Table No. I-Examples 1-4

Example Sorb. water / wt. OF/ ' Surface appearance Structure appearance 1 0.2 smooth even distribution pore sizes 2. 2.1 smooth, in places even distribution the formation of blisters pore size 3 A, 2 continuous layer small blisters uniform, local deformation of structure 4 12.0 continuous layer big blisters warped structure

It follows from Examples 1-4 that a hydrophilic additive having a sorbed water content of up to 2 wt. X.

Examples 5-17

According to Examples 1-4, surface formations were prepared which differed in the content of the hydrophilic additive of polymethacrylate Na, crosslinked with 20% of divinylbenzene containing 0.2 wt. From sorbed water and blowing agent content in the cover layer. The content of both additive and blowing agent is given in mass. Z, based on the weight of the polymer. Plastisol for the base layer in all cases contains 2 wt. From the blowing agent, in Examples 6-17, 40 wt. From the additive and in Example 5, the additive does not contain.

The values of important parameters were determined for individual surface formations.

The measured values are given in Table II.

Ex. Plastisol for liner Parameters of the cover layer Base layer parameters Additive / weight content Zl Content blowing agents / wt. % / Size pores / mm / Bulk density t / kg / m ³ / Size pores / mm / Density. / kg / m ^J / 5 0 0 - - 0.38 422 6 0 0. - - 0,3 2 401 7 10 0 0.06 1 038 0.45 443 8 .20 0 0.10 993 0.39 429 9 30 0 0.08 1 066 0.41 451 10 40 O 0.07 1 020 0.49 46 2 1 1 50 '0 0.09 982 0.37 415 12 30 0.5 0.14 658 0.46 451 13 40 0.5 0.11 702 0.32 390 ' 1 4 50 0.5 0,1 2 683 0.36 408 15 Dec 30 1 0.16 602 0.39 420 16 40 1 0.19 581 0,4 7 449 1 7 50 1 0.17 635 0.50 471 Table No II - to Examples 5 - 17 '

Ex. Area parameters Thickness (mm) Flat hm- nost Navlhavoet ₁ / mg / cm / High wax t / Z mass Water vapor permeability ₂ / mg / cm h / Appearance after repeated movement Use of sorption capacity of additive / mg H ₂ 0 vapor / mg additive / Abrasion resistance 5 1.30 851 0 - 0.2 unchanged - 5 6 1.01 831 1, 1 - 0.2 unchanged 0.15 4 7 1.10 872 2.5 19 Dec 0.3 unchanged 0.31 4 8 1, 08 846 4.3 21 0.4 unchanged 0.48 4 9 1.15 810 5.8 25 0.3 slight color change at the bend 0.59 4 10 1, 06 861 10.1 33 0.4 Significant color change at the bend 0.97 4 1 1 0.98 822 13.6 36 0.5 Significant color change at the bend 1,22 4 12 1, 16 824 12.2 64 0.9 unchanged 1,25 4 13 1, 09: 81 1 14.3 70 0.8 slight color change at the bend 1, 37 4 14 1.13 849 16.9 66 1.1 Significant color change at the bend 1.52 4 15 Dec 1.20 865 14.8 68 0.6 unchanged 1.52 3 16 1.15 840 17.2 73 0.5 unchanged 1.65 3 17 1.11 819 19.5 79 13 slight color 1.75 3

change at the bend

Examples 5-17 show a positive effect of the blowing agent in the cover layer on the hygiene properties of the sheet. 0.5 wt. From the blowing agent, it significantly reduces the unfavorable effect of the color change at the points of repeated movement. The appearance after repeated bending is affected by the additive content.

Examples 18-21

According to the preceding examples, surface formations were prepared which differed in the content of the hydrophilic additive of polymethacrylate Na, sieved 20 2 divinylbenzene, containing 0.2 wt. 2 sorbed water in plastisol for base layer.

Plastisol for the topcoat contained 40 2 hydrophilic additives and 0.5 wt. 2 blowing agents of azodicarbonamide. The content of both additive and blowing agent is given in masses, 2 based on the weight of the polymer. A non-woven fabric based on polyester / polypropylene / viscose was applied from the group of backing fabrics.

T a Ex. The results are bulka č, Polymeta- krylan Na / wt. 2 / listed in the table III - to examples Thickness / mra / No III. 18-21 Vysýchavos t lil Permeability for water couple / mg / c and h / Flat material. / g / m ² / Humidity / mg / cm 2 1 8 10 0.9 762 8.3 62 0.4 19 Dec 20 May 0.92 753 10.2 68 0.5 20 May 40 0.96 772 13.9 70 0.7 21 60 1, 05 761 15.1 71 0.6

Examples 18-21 show that with increasing additive content in plastisol for the base layer, while maintaining a constant amount of additive in plastisol for the cover layer, the wetting of the sheet produced according to the invention increases.

The upper limit of the additive content is given by the viscosity behavior of plastisol. When using 75 or more wt. 2 additives have plastisols of very high viscosity and cannot be processed by the process according to the invention.

Example 21 - 25

According to the previous examples, surface formations were prepared which differed in the type of hydrophilic additive used. All applied additives were crosslinked with 20 2 divinilbenzene, Plastisol for the coating layer contained 0.5 wt. 2 blowing agents, the additive content / 40 wt. 2) was the same for both plastisol for the topcoat and for the base layer. In Examples 22-25, a vinyl chloride-vinyl acetate copolymer was used. The vinyl chloride content was 5 2,

Polyester / cotton knitwear was applied from the backing fabric group.

The results are shown in Table IV.

Table IV - Examples 22 - 25

Ex. Hydrophilic additive * .. · .j s and h sorbed water in additive / wt. OF/ Thickness / mm / Flat material. / g / m ² / Moisture t / mg / cm 7 Drying Λ hmo t. / Water vapor permeability ₂ / mg / cin h / 22nd polyacrylan Na 0.6 1.19 875 14.8 67 0.6 23 polymethacrylan Na 0.2 1.17 859 13.5 69 0.4 24 polyglycplmethacrylate 0.9 1,22 888 4.0 59 0.5 25 polyacrylamide "IF........... 1.16 870 6.8 61 0.3

Examples 21-25 show that polyacrylate Na and polymethacrylate Na are the most suitable hydrophilic additives for the sheet according to the invention.

Example 1 and d 26

In Example 26, a second process was used to produce the sheet according to the invention. Plastieol for opaque / 0.5 wt. 2, the blowing agent / base layer contained 40 wt. % additive. A polyester / viscose woven fabric was applied as a backing layer.

The produced surface formation was additionally embossed.

The measured values of the parameters corresponded to those obtained in Example 13. From this it is clear that the same basic properties of the sheet formation according to the invention will be achieved by both methods.

The surface formulations prepared according to the invention are characterized by high water vapor sorption and desorption and are particularly suitable for application as upholstery materials for passenger cars and vehicles of all kinds, seating furniture sets, as well as footwear lining and top materials for summer sandal shoes. In view of the above-mentioned applications, it is necessary to further finish the surface formations with polyurethane-based lacquers by conventional techniques. The recipe of the surface treatment must be chosen in such a way that the achieved water vapor sorption is maintained or there is only a minimal reduction.

Claims (1)

OBJECT OF REMOVE A three-layer sheet capable of absorbing water vapor consisting of two different lightweight polyvinyl chloride-based polymers, vinyl chloride copolymers or mixtures thereof containing plasticizers, stabilizers, blowing agents, catalysts, lubricants, dyes and hydrophilic additives based on cross-linked macromolecular substances and by simultaneously blowing plastisol of polyvinyl chloride containing 0.3 to 1.0% by weight of azodicarbonamide and 10 to 40% by weight of hydrophilic additive to the topsheet and plastisol of vinyl chloride poles containing 1.0 to 3.0% by weight of azodicarbonamide and 10 to 70% by weight a hydrophilic base layer additive, all based on the weight of the polymer, wherein the hydrophilic additive based on crosslinked macromolecular substances prepared by polymerizing vinyl monomers and containing polar groups capable of binding water such as hydroxyl, and mídová as above + ^f + _v HODO carboxyl groups in the H, Na, and K ^ form comprises 0.1 to 20 by weight of the water sorbed ^ calculated on the weight of the hydrophilic additive.