HU204581B - Method for coating paper, textile and foil-like products with silicone layer - Google Patents

Abstract

Paper, textile and foil type substrates are pretreated prior to silicone coating. The pretreating agent contains a mixt. of esters of orthosilicic (RO)nSi(OC2H4Cl)4-n (I); ortho-boric-, B(OR)3 (II); and ortho-titanic-, Ti(OR)4 (III); -acids. R = 1-4C straight chain alkyl gps. and n = 0, 1, 2, 3 integers. The concn. of (II)+(III) = 5-40%, and in this the pretreating mix also contains a solvent. The thin topcoat is based on di:methyl-siloxane polymer with silanol end gps. (IV) and also contains a crosslinking agent (V) with at least three Si-H or Si-OR functional gps. per each molecule and a metal carboxylate type condensn. catalyst (VI).

Description

BACKGROUND OF THE INVENTION The present invention relates to a process for making a paper, textile or film-like product suitable for coating with a silicone layer by treating a paper, textile or film-like substrate prior to coating, ortho-tartaric acid ester and / or ester of orthoboric acid with chloroethoxy groups. mixture.

It is known that papers, textiles, and films coated with a methyl polysiloxane rubber layer can be used in a wide variety of applications for packaging adhesive materials, e.g. as a protective and packaging material for bitumen, sugary products, sticky materials, pressure-sensitive adhesive labels, wallpapers, and as a backing for the production of films, synthetic leather and foamed plastics The excellent release effect on organic materials is due to the addition of methyl polysiloxane rubber see, e.g., DJ Gordon, JA Colquhoun: Surface Properties of Silicone Release Coatins, Age of Adhesives, June 1976,21.0).

Methyl polysiloxane rubber has to be formed on a very thin layer of 0.0010.1 mm in thickness in order to have a good mechanical resistance and abrasion resistance of the rubber layer, and the thick layer rubber is more sensitive to mechanical stress. At the same time, for a good release effect, a very smooth, fault-free silicone layer must be formed on the substrate surface which is very adherent to the substrate.

The methyl polysiloxane rubber coating has been found to be useful in the use of a dimethyl polysiloxane polymer containing active silanol end groups which is crosslinked on the support surface with an oligosiloxane containing at least three (SiR'HO) units per molecule, i.e. reactive Si-H bond. in the presence of dibutyltin dilaurate as disclosed in British Patent No. 804,198. In the (SiR'HO) unit, R 'represents a lower alkyl group, typically a methyl group. Dimethylpolysiloxane polymer containing active szilanolvégcsoportokat térhálósítá- ^one attention orthosilicic acid esters, e. tetraethyl silicate or a polymer obtained by its partial hydrolysis, the so-called. ethyl polysilicate may also be used, as disclosed in U.S. Patent No. 2,843,555. Yes preferred crosslinking agent can be prepared as alkyl silicates and ^z used as the catalyst metal carboxylate, for example. by preheating the mixture of dibutyltin dilaurate to 50-250 ° C, as disclosed in British Patent No. 936,408.

The so-called Afenti cold-vulcanizing silicone rubber systems are in principle suitable for coating paper, textile and web-like products pretreated by the process of the present invention with a thin film of form release silicone. Practical implementation shows that not all types of paper, textiles and foils are suitable for direct coating, and the vast majority of paper products cannot be applied without pre-treatment.

For proper durability, a coating sufficiently adhering to the substrate can be obtained only after the substrate has been pre-treated. In particular, film-like products, such as the coating of polyester and polyvinyl chloride films with a silicone layer requires pre-treatment with an adhesive. As such an adhesive, aminoalkylsilanes used to treat the surface of glass fibers to epoxy resins, e.g. 3 amino-propyltriethoxysilane proved to be effective. Making the paper carrier suitable for silicone can be achieved by greatly reducing the amount of absorbent paper, the so-called. types of parchment paper, [0] or high calendered papers are used to produce siliconized paper. The need for both aminoalkyl silane pretreatment and the need for high value paper products greatly increases the cost of production, thus limiting the scope of otherwise versatile silicone papers, textiles and films. This cost-increasing effect is particularly disadvantageous for self-adhesive labels and tapes, where the cost of producing discarded back paper is greater than the cost of producing an adhesive label that is actually used.

In our attempts to more economically coat paper, textile, and film-like products with a silicone layer, we have found that papers made with conventional 5 technologies, e.g. stationery grade papers as well as inexpensive kraft papers and other general purpose papers can be made easily and economically suitable for silicone coating when the paper is characterized by the formula (RO) _n Si (OC2HtCl) 4. ) With a mixture of _3- composition orthoboric acid ester and / or Ti (OR) _4- composition orthotitanoic acid ester, wherein R is a C 1-4 alkyl group, the same or different, such as methyl, ethyl, n-propyl) or n- denotes butyl and n-0, 1, 2 or 3. Such a composition has proven to be very effective in textiles, e.g. fiberglass and polyamide fabrics; and films, e.g. treatment of cellophane and plasticized polyvinyl chloride film prior to silicone coating. As a result of the treatment, the silicone rubber layer adheres very well to a smooth and error-free coating with simple lubrication, dipping, spraying, roller or air jet technology.

The substrates treated by the process according to the invention, especially the cheaper base papers, have the great additional advantage that the occasional unevenness of the applied silicone layer or the local lack of the very thin layer of the coating does not cause any difficulty in its use. shows some degree of release effect.

The (ROjnSiíOCzHiCl) *.,! The ortho-silicic acid ester represented by the formula (III) may be prepared from the ortho-silicic acid ester of the formula (RO) ₄ Si by heating with ethylene-chlorohydrin. For example, a 1: 2 molar mixture of tetraethylsilicate and ethylene chlorohydrin yields ethanol as a distillate to give the reaction product (C ₂ H ₃ O) 2 Si (OC ₂ H ₄ Cl) 2 as the main product in which (C 2 H ₅ O) ₃ Si (OC ₂ H ₄ Cl). ) Si (OC ₂ H ₄ Cl) ₃ is a by-product. The

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Such a mixture can be used directly in the process of the invention.

Each of the treatment agents used in the process of the present invention reacts with water and, upon leaving the alcohol-type compounds, is converted to siloxane-bonded, borosiloxane-bonded, titanosiloxane-bonded polymeric compounds which retain more or less Si-OR-type functional groups. This type of functional group is capable of forming a chemical bond with the reactive silicone rubber mixture when the silicone rubber layer is formed, which may explain the excellent adhesion.

When searching for the optimum composition of the drug, it was found that in addition to the ortho-tartaric acid ester represented by the formula (ROjnSiCCXZytliCl) ^, at least 5% B (OR) 3 orthoboronic acid ester and / or 5% Ti (OR) ₄ orthotitanoic acid ester but not more than 40% by weight of the boric acid ester and the titanium acid ester combined. Larger amounts of titanium acid ester can cause fragility of base paper, while excess amounts of boric acid ester in the form of crystalline boric acid precipitation can be interfering. The optimum amount for both materials is between 10201%. The treatment is preferably carried out in the form of a solvent solution for papers and textiles, the solvent being anhydrous solvents, e.g. gasoline, alcohols may be used. The degree of dilution can be well adjusted to the desired coat weight. After evaporation of the solvent, the treatment agent solidifies at room temperature for a few minutes under the influence of air humidity and adsorptive moisture on the substrate, and it is desirable to accelerate the process by heating. The silicone layer should be applied after at least one hour after application.

A preferred embodiment of the process according to the invention is the addition of the condensation catalyst used in the art-known silicone technology, the dialkyltin carboxylates, which are the most well-known in practice, to the dual benefit of solidifying the support itself in less time. on the other hand, the life of the silicone mixture is not shortened by the presence of the catalyst. The applied silicone layer is crosslinked by the catalyst already present on the carrier

Thus, the present invention relates to a process for coating paper, textile and film-like products with a silicone layer, characterized in that the substrate to be coated with the silicone layer is an ortho-silicic acid ester (I) characterized by the formula (RO) "Si (OC ₂ HtCl) 4. With a mixture of B (OR) 3 orthoboric acid ester (Π) and / or Ti (OR) ₄ orthotitanoic acid ester (ΙΠ), wherein R represents a C 1-4 straight or different alkyl group and n-0, 1 , An integer of 2 or 3, wherein the mixture contains (Π) and / or (ΠΙ) 5-401%, optionally diluted with a solvent, and dimethylpolysiloxane polymer containing at least three Si-H or Si -OR 'crosslinking agent, wherein R' is thin with a mixture of a lower alkyl group and a metal carboxylate condensation catalyst layer.

The following representative examples of the process of the invention are given:

Example 1 A mixture of 10 parts by weight of diethoxy-dichloroethoxysilane, 10 parts by weight of triethyl borate and 20 parts by weight of tetran-n-butyl titanate was diluted with 200 parts by weight of medium absorbent carrier paper with 100 g / m ² . . After two hours of rest, the treated paper is a dry, slightly translucent paper of 120 g / m ² . For forming the silicone coating, 100 parts by weight of dimethyl polysiloxane having reactive silane end groups having a viscosity of 50,000 mPa · s, 3 parts by weight tetraethoxysilane, 1 part by weight viscosity 20 mPa · s, methyl hydrogen polysiloxane oil and 1 part by weight dibutyl To the mixture was added 1000 parts by weight of light petroleum and 100 parts by weight of n-butanol. The product is a silicone paper which, with a very good form release properties, peel off a strip of film coated with a polyvinyl acetate self-adhesive adhesive at a force of 5 N / m.

Example 2

In the same manner as in the first example, the same 100 g / m ² medium absorbent carrier paper is directly coated with the silicone solution without pre-treatment and then snow-cured at 120 ° C for 4 minutes. The resulting silicone paper absorbs from 6 to 10 times the amount of silicone solution as the paper pretreated in Example 1 and has an inadequate resolution, sometimes causing a tear on the siliconized paper when peeling off the polyvinyl acetate self-adhesive film.

Example 3

In a manner similar to that described in Example 1, 20 parts by weight of tetra-n-butyl titanate and 20 parts by weight of dibutyltin dilaurate were mixed with 80 parts by weight of ethyl trichloroethoxysilane and tetrachloroethoxysilane in 1: 1 and diluted with 300 parts by weight of i-propanol. the resulting solution is treated with a high absorbent kraft paper having a weight of 160 g / m ² . The paper was dried at 60 ° C for 10 minutes, followed by 100 parts by weight of 60,000 mPa · s viscosity, silane end-capped dimethyl polysiloxane, 2 parts by 20 mPa · s viscosity methyl hydrogen polysiloxane oil, 900 parts by weight light naphtha and 100 parts by weight i-propanol. To the mixture was added 1 part by weight of dibutyltin dilaurate and the paper was coated with the solution and finally dried in a drying tunnel at 70 ° C for 3 minutes. The resulting silicone paper is well suited for use as a backing paper on a self-adhesive side of wallpaper with a release force of 8-10 N / m.

Example 4 To a mixture of part by weight of diethoxy dichloroethoxysilane, 5 parts by weight of tri-n-butyl borate and 5 parts by weight of tetra-n-butyl titanate is added 30 parts by weight of dioctyltin maleate, followed by

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210 g / m ² dipped in fiberglass dressing. After 24 hours of rest, the treatment was repeated on both sides with a silicone solution of the same composition as in Example 3 but without organic tin catalyst, and treated at 160 ° C for 2 minutes. The silicone rubber-coated glass fabric thus obtained is well suited for producing an endless strip for a continuous baking apparatus for sugar biscuits.

Example 5 To a mixture of 1 part by weight of ethyl trichloroethoxysilane, 5 parts by weight of triethyl borate and 15 parts by weight of tetra-n-butyl titanate are added 30 parts by weight of dibutyltin dilaurate and 100 parts by weight of perchlorethylene. With this solution, rub the surface of the desired hard PVC film in my hands, heat it at 80 ° C for 2 minutes, then lubricate it with the composition of Example 3, and reheat it for 2 minutes at 80 ° C. The silicone film is suitable for use as a backing film for urethane foam.

Example 6

In a similar manner to that described in Example 3, a paper bag of 120 g / m ² was used to make paper bags and siliconized. Silicone paper used as inner paper for double layer paper bag

581 B 2 is obtained into which the bitumen can be warmly loaded and the bag can be removed from the bitumen without difficulty during use. -

Claims (2)

• PATENT CLAIMS A process for coating paper, textile and film-like products with a silicone rasp, characterized in that the carrier material to be coated with the silicone layer is an ortho-boronic acid ester (I) and B (OR) ₃ , characterized by the formula (ROJaSiIIOCjHfCl) A mixture of H) and / or Ti (OR) 4 orthotitanic acid ester (ΙΠ), wherein R represents a C 1-4 linear or identical straight chain alkyl group and n-0, 1, 2 or 3 in which Π) and / or (HE) in an amount of 5-401%, optionally diluted with a solvent, and dimethylpolysiloxane polymer containing silane end groups known per se, crosslinking agent containing at least three Si-H or Si-OR 'functional groups - wherein R' is a thin layer known in the art with a mixture of a lower alkyl group and a metal carboxylate condensation catalyst. 2. A process according to claim 1, wherein the metal carboxylate condensation catalyst is added to the treatment composition (MI and / or ΙΠ).