JPS6356356B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a fixing agent used for fixing a fabric to a printing table in the printing process of textile printing, particularly screen printing. Conventionally, the following adhesives have been used: Aqueous solutions of water-soluble polymer substances such as starch paste, carboxymethyl cellulose, polyvinyl alcohol, and polyacrylamide Heat-fusible substances such as paraffin, wax, and rosin Vinyl acetate resin, ethylene-vinyl acetate copolymer, acrylic resin Emulsions or latexes of thermoplastic resins such as rubber-based, acrylic-based, silicone, etc. pressure-sensitive adhesives Adhesive tapes for applying the above-mentioned pressure-sensitive adhesives However, each of these adhesives has drawbacks. In other words, in the case of hydrophilic natural fibers such as silk and cotton, after printing, the fabric is re-moistened with water from the printing paste, and the fabric rises from the printing table due to shrinkage due to drying of the printing paste, resulting in multicolored The design on the stamp is misaligned. In addition, in the case of hydrophobic synthetic fibers such as polyamide and polyester, the water in the printing paste is not adsorbed by the fibers but spreads to the back side of the fabric, impeding the adhesion of the adhesive. Not only will the print stand out even more (floating), but the color will also come out during the next printing (remaining color). In addition, cleaning after each printing process,
It is troublesome because it requires repeated reapplication.
In addition to having weak adhesive strength, paraffin and other substances adhere to the fabric in the areas pressed by the screen during screen printing and melt during heat treatment after printing. Although it depends on the affinity between the resin used and the fabric or printing paste, if the adhesiveness is too strong, the resin used as a adhesive will transfer to the fabric (resin removal), and when the fabric is peeled off, The printing paste transfers to the adhesive (glue residue) and contaminates the adhesive, so it is necessary to reapply the adhesive or wash the adhesive surface with water each time. If the force is weak, the fabric will shift during printing, resulting in poor pattern fit.
cannot provide sufficient tension to the fabric. For these reasons, it is most preferable to use pressure-sensitive adhesives as adhesives, but even if such adhesives are used, for example, in the case of rubber-based or acrylic-based pressure-sensitive adhesives, the following There are drawbacks such as. That is, when the fabric is peeled off after printing and drying, the printing paste is absorbed by the adhesive, causing uneven dyeing on the fabric surface. When the cloth is peeled off after printing and drying, due to the destruction phenomenon between the layers of the printing lake, colored paste powder is generated, causing color scattering. Because the base agent becomes contaminated with colored paste, the color transfers when printing is performed next time. If the adhesive strength of the adhesive to the fabric is too strong, pattern deviations within the thread will occur due to twisting of the thread, while if it is too weak, problems such as lifting and shrinkage will occur. When using a silicone-based pressure sensitive adhesive as described in JP-A-54-30989, the above-mentioned
However, with repeated use, both the adhesive strength and releasability decrease, making it impossible to straighten the fabric (grain correction), and it is often necessary to apply a top coat of adhesive during use. This needs to be supplemented. The present inventors conducted research with the intention of resolving these drawbacks of conventional adhesives, and as a result, found that adhesiveness, adhesiveness,
We have discovered a adhesive that has excellent releasability after printing, has a good balance between the two, and is free from defects such as uneven dyeing, color scattering, pattern raising, pattern shift, lifting, and shrinkage, and has thus achieved the present invention. . That is, the present invention provides (1)(A) R ¹ ₃ SiO _1/2 units per mole of SiO ₂ units (wherein R ¹ is the same or different substituted or unsubstituted monovalent hydrocarbon) (indicates the group) 0.4
In a proportion of ~1.0 mol, substantially SiO ₂ units and R ¹ ₃
30 to 80% by weight of a benzene-soluble polyorganosiloxane resin consisting of SiO _1/2 units and having 0.0004 to 1 reactive group bonded to silicon atoms per silicon atom; (B) a viscosity of 10000 to 200 million cP at 25°C; Silanol-terminated polydiorganosiloxane with 20
100 parts by weight of the condensation reaction product with ~70% by weight, (2) Substantially the general formula R ² ₃ SiO [R ³ ₂ SiO] _o SiR ² ₃ (wherein R ² and R ³ are an alkyl group and Mutually identical or different monovalent hydrocarbon groups selected from the group consisting of phenyl groups, n is 4 to 1000
Indicates the number of R ² and R ³ in the molecule,
50 mol% or more of which are methyl groups), and cyclic polydimethylsiloxanes represented by the general formula [(CH ₃ ) ₂ SiO] _n (where m represents a number from 4 to 6). 40 to 200 parts by weight of a polydiorganosiloxane selected from the group consisting of; (3) 30 to 200 parts by weight of an acrylic resin; and (4) 100 to 2000 parts by weight of an organic solvent. Regarding drugs. (1) used in the present invention is a product obtained by co-condensing the benzene-soluble polyorganosiloxane resin (A) with the silanol-terminated polydiorganosiloxane (B). The blending ratio of both is in the range of 30 to 80% by weight of (A) based on the total amount of (A) and (B). This is because if (A) is too small, good adhesion cannot be obtained, and if it is too large, the cured film becomes too hard and the adhesion is reduced. The benzene-soluble polyorganosiloxane resin (A) is composed of SiO ₂ units and R ¹ ₃ SiO _1/2 units (where R ¹ is as described above) and has a relatively low molecular weight. R ¹ is a methyl group,
Alkyl groups such as ethyl group, propyl group, butyl group, amyl group, hexyl group, octyl group, decyl group, alkenyl groups such as vinyl group, aralkyl groups such as β-phenylethyl group, aryl groups such as phenyl group, and Examples include those in which some of the hydrogen atoms of are substituted with chlorine atoms, fluorine atoms, nitrile groups, etc., but they are easy to synthesize, have good weather resistance, and are highly reactive with (B). Therefore, it is preferable that 90 mol% or more of R ¹ is a methyl group, and it is particularly preferable that all of R ¹ is a methyl group. The amount of R ¹ ₃ SiO _1/2 unit is SiO ₂ unit 1
It is between 0.4 and 1.0 mol. If there are too few R ¹ ₃ SiO _1/2 units, it is difficult to stably obtain a benzene-soluble, low-molecular-weight polymer, and it tends to gel during synthesis or storage, resulting in an insoluble and infusible polymer. Also R ¹ ₃
If there are many SiO _1/2 units, the reactivity during condensation with the silanol-terminated polydiorganosiloxane (B) will decrease. Reactive groups bonded to silicon atoms include hydroxyl group, methoxy group, ethoxy group, propoxy group,
Examples include butoxy group, methoxyethoxy group, and ethoxyethoxy group. Such polysiloxane resins are made by combining a tetrafunctional silicon-containing compound selected from alkyl silicates such as ethyl silicate and propyl silicate, partial condensates thereof, silicon tetrachloride, and water glass, and adding trimethylchlorosilane in the presence of a solvent. ,
It can be obtained by cohydrolyzing with a triorganochlorosilane such as dimethylvinylchlorosilane or dimethylphenylchlorosilane and removing by-products by conventional means. As a solvent,
Benzene, toluene, xylene, gasoline, n-
Hydrocarbons such as hexane and n-heptane are commonly used. As the silanol-terminated polydiorganosiloxane (B), one having a substantially linear siloxane skeleton and a viscosity of 10,000 to 2,000,000 cp at 25°C is used. If the viscosity is less than 10,000 cP, the resulting film will have poor toughness and flexibility, and if it exceeds 2,000,000 cP, the viscosity of the composition will increase, impeding workability. The organic group bonded to the silicon atom is exemplified by the same one as R ¹ in (A), and the balance between viscosity and necessary physical properties, reactivity in condensation with polysiloxane (A), and Although it is preferable that all of them are methyl groups because they are easily obtained and relatively easy to synthesize, an appropriate amount of phenyl groups may be introduced depending on the use and required properties. Co-condensation of the polysiloxane resin (A) and the silanol-terminated polydiorganosiloxane (B) is carried out by mixing the two and heating preferably in the presence of caustic potash or caustic soda. The polysiloxane resin (A) usually has a solid content of 30~
It is obtained as a 60% by weight hydrocarbon solution, but an organic solvent is added if necessary, then the silanol-terminated polydiorganosiloxane (B) is added, and the mixed system is heated. The organic solvent used is preferably a hydrocarbon solvent, with toluene or xylene being particularly preferred. The heating temperature is preferably between 80 and 150°C, and it is particularly advantageous to use the reflux temperature of the added solvent in terms of temperature control. It is preferable not to allow this condensation reaction to continue until completion, but to stop it when components (A) and (B) form a homogeneous phase and become a transparent solution. The polydiorganosiloxane (2) used in the present invention not only imparts appropriate releasability to the adhesive, but also imparts tackiness when (1) is relatively hard and lacks tackiness. It is a stable polysiloxane that is liquid at room temperature and has a chain or cyclic siloxane skeleton. Examples of R ² and R ³ of the substantially chain polydiorganosiloxane include alkyl groups such as methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, and decyl groups, and phenyl groups. However, in order to obtain good releasability, it is necessary that methyl groups account for at least 50 mol% of the total, and that it is easy to synthesize, has excellent releasability, and is compatible with (1). From solubility,
Preferably, all groups are methyl groups. n is 4~
Between 1000 and preferably between 10 and 100. If n is less than 4, the chain siloxane will have a low boiling point and will volatilize during use, making it unsuitable for practical use. If n exceeds 1000, the viscosity will increase and it will be inconvenient to handle. In the case of cyclic polysiloxane, it is easy to synthesize, is abundantly obtained as an intermediate for other polysiloxanes, and is liquid, so the organic group bonded to the silicon atom is a methyl group and m is in the range of 4 to 6. are used. There is no problem even if some substances with m of 3 are mixed in, but this substance itself is solid at room temperature, so
It can only be used as such a mixture.
Among these polysiloxanes, chain polysiloxanes are suitable for adhesives in terms of providing releasability. The amount of polydiorganosiloxane in (2) is
40 to 200 parts by weight per 100 parts by weight, preferably 80 parts by weight
~150 parts by weight. If the amount of (2) is less than 40 parts by weight, the peelability will be poor, and if it exceeds 200 parts by weight, the adhesive will become soft and stringy. The acrylic resin (3) used in the present invention is a polymer or copolymer of acrylic or methacrylic monomers such as acrylic acid, its ester, acrylamide, or a functional derivative thereof. Furthermore, a copolymer of 20 mol % or less of a vinyl monomer such as vinyl acetate with the above-mentioned monomers may also be used. The blending amount of the acrylic resin (3) is in the range of 30 to 200 parts by weight, preferably 80 to 150 parts by weight, based on 100 parts by weight of (1). If the acrylic resin is less than 30 parts by weight, it will not have sufficient hardness as a adhesive.
If it exceeds 200 parts by weight, sufficient adhesive strength may not be obtained or color staining may occur. The organic solvent (4) used in the present invention is used to dissolve (1) to (3) to make it easier to apply, and includes benzene, toluene, xylene, n-hexane, n-heptane, cyclohexane, and gasoline. Examples include hydrocarbons such as carbon tetrachloride, and halogenated hydrocarbons such as trichloroethylene. Among these, toluene and xylene are preferred because of their appropriate volatility, solubility of (1) and (2), and ease of handling. The amount of organic solvent in (4) is 100 parts by weight per 100 parts by weight of (1).
-200 parts by weight, preferably 300-1000 parts by weight. If it is less than 100 parts by weight, the viscosity of the thread increases, making it difficult to coat and poor storage stability. If it exceeds 2000 parts by weight, a film of sufficient thickness cannot be obtained, which is economically disadvantageous. The adhesive of the present invention may contain resins such as polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, and ethylene-vinyl acetate copolymer, if necessary. Further, inorganic fine powder such as silica, talc, calcium carbonate, and liquid paraffin may be added. The adhesive of the present invention has excellent adhesion and peelability after printing, has a good balance between the two, and is free from defects such as uneven dyeing, color scattering, drawing up, pattern shift, lifting, and shrinkage. According to the present invention, a useful grounding agent suitable for textile printing was obtained. Hereinafter, the present invention will be explained with reference to Examples. In the following Examples and Comparative Examples, all parts represent parts by weight. Example 1 Consisting of SiO ₂ units and (CH ₃ ) ₃ SiO _1/2 units, the ratio of (CH ₃ ) ₃ SiO _1/2 units to 1 mol of SiO ₂ units is 0.65 mol, and the hydroxyl group to be bonded to the silicon atom is To 150 parts of a 50% xylene solution of polyorganosiloxane resin, add 25 parts of silanol-terminated polydimethylsiloxane with a viscosity of 7,000,000 cP at 25°C, dissolve uniformly, then add 0.02 part of a 10% aqueous solution of caustic soda, and stir. The mixture was heated to the reflux temperature of xylene for 3 hours to advance condensation. Then
Cool to 35℃ and neutralize with 10% phosphoric acid aqueous solution.
After evaporation, xylene was added to prepare a 50% xylene solution S-1 of the polysiloxane condensation reaction product. To this, the above-mentioned S
-1, trimethylsiloxy-terminated linear polydimethylsiloxane F-1 with a viscosity of 50 cP at 25°C,
Samples 11 to 14 according to the present invention and Comparative Example Sample 15 were prepared by blending acrylic resin solution A-1, octamethylcyclotetrasiloxane, and toluene, which will be described later.
~17 were prepared. Using these samples as a base agent, a polyester fiber cloth was pasted on a wooden printing stand whose surface had been treated with urethane resin, and printing was performed using the over glue and anti-discharge printing paste shown below. The characteristics were investigated.

【table】 %.

[Table] That is, 80 to 90 g/m ² of the sample was applied to a printing stand, dried, a polyester fiber cloth was attached, and printing was performed at about 30°C by the top heating method (heating with hot air). Table 2 shows the hardness of the cured adhesive layer, the adhesive strength during printing at the initial stage and after 80 repeated uses, the peelability after printing, resin removal, and other findings. However, the fabric is pasted on a printing stand on which a layer of adhesive has been formed, and the printing is done once with the anti-bleeding agent and once with the overglue, and then the printed fabric is peeled off. The process can be counted as one time.
In addition, Comparative Example Sample 17 caused phase separation after preparation and did not form a uniform adhesive layer.

【table】

[Table] Example 2 In the same manner as S-1 shown in Example 1, various polysiloxane condensation reaction product solutions S-2 to S-6 were obtained as shown in Table 3. Using these polysiloxane condensation reaction products, samples 21 to 27 having the compounding ratios shown in Table 4 were prepared. Using the sample thus obtained, printing was carried out under the same conditions as in Example 1. The results were as shown in Table 5.

[Table] Exists as a unit.

【table】

【table】

[Table] (Note) *1 to *4: Same example as in Table 2 3 Samples 31, 32 were prepared. A-2: Toluene solution of copolymer of 75% by weight of 2-ethylhexyl methacrylate and 25% by weight of 2-ethylhexyl acrylate, solid content 35% The same experiment as in Example 1 was conducted on these samples. The results are shown in Table 2.

Claims (1)

[Claims] 1 (1) (A) R ¹ ₃ SiO _1/2 units per mole of SiO ₂ units (wherein R ¹ is the same or different substituted or unsubstituted monovalent carbonized (indicates hydrogen group)
In a proportion of 0.4 to 1.0 mol, substantially SiO ₂ units and
30 to 80% by weight of a benzene-soluble polyorganosiloxane resin consisting of R ¹ ₃ SiO _1/2 units and having 0.0004 to 1 reactive group bonded to silicon atoms per silicon atom; (B) 10000 to 20000000 cP at 25°C; Silanol-terminated polydiorganosiloxane with a viscosity of 20
100 parts by weight of the condensation reaction product with ~70% by weight, (2) Substantially the general formula R ² ₃ SiO [R ³ ₂ SiO] _o SiR ² ₃ (wherein R ² and R ³ are an alkyl group and Mutually identical or different monovalent hydrocarbon groups selected from the group consisting of phenyl groups, n is 4 to 1000
of the total of R ² and R ³ in the molecule, 50
linear polydiorganosiloxane (at least mol % of which is a methyl group), and cyclic polydimethylsiloxane represented by the general formula [(CH ₃ ) ₂ SiO] _n (where m represents a number from 4 to 6). 40 to 200 parts by weight of a polydiorganosiloxane selected from the group consisting of; (3) 30 to 200 parts by weight of an acrylic resin; and (4) 100 to 2000 parts by weight of an organic solvent. agent. 2. Claim 1, in which R ¹ is a methyl group
Adhesive agent as described in section. 3. The adhesive according to claim 1, wherein the reactive group bonded to the silicon atom in (A) is a hydroxyl group. 4. The adhesive according to claim 1, wherein the organic group bonded to the silicon atom in (B) is a monovalent hydrocarbon group selected from the group consisting of a methyl group and a phenyl group. 5. The adhesive according to claim 4, wherein the organic group bonded to the silicon atom in (B) is a methyl group. 6. The adhesive according to claim 1, wherein the polydiorganosiloxane (2) is 80 to 150 parts by weight. 7. The adhesive according to claim 1, wherein the acrylic resin (3) is contained in an amount of 80 to 150 parts by weight.