JPH0845070A - Surface treating agent for plastic film - Google Patents

Abstract

PURPOSE:To obtain an aq. surface treating agent for a plastic film imparting lubricity and fusion preventing property, excellent in adhesion to the substrate and forming a hardened film having no migrating property. CONSTITUTION:An aq. dispersion of nonflowable branched silicone having constituent units represented by the gernal formulae R<1>2SiO2/2 and R<1>SiO3/2 (where R<1> is 1-20C optionally substd. monovalent hydrocarbon) is used as a lst component. An aq. dispersion of a product obtd. by hydrolyzing and condensing dialkoxysilane represented by the general formula R<2>R<3>N(CH2)a[NR<4>(CH2) b]cSiR<5>(OR<6>)2 (where each of R<2>-R<4> is H or 1-6C optionally substd. monovalent hydrocarbon, each of R<5> and R<6> is 1-6C optionally substd. monovalent hydrocarbon, 1<=a<=6, 1<=b<=6 and 0<=c<=3) is used as a 2nd component. Aq. urethane resin is used as a 3rd component. The 1st, 2nd and 3rd components are mixed so that the effective components are contained by 9-90wt.%, 0.1-40wt.% and 9-90wt.%, respectively.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aqueous surface treatment agent for plastic films. The surface treatment agent of the present invention is suitable as a surface treatment agent for a base material of a heat-sensitive transfer sheet or a magnetic tape.

[0002]

2. Description of the Related Art Conventionally, plastic films have been used as base materials for heat-sensitive transfer sheets and magnetic tapes. The thermal transfer sheet causes a phenomenon in which the base film is fused with the thermal head when performing thermal printing from the back side, so-called sticking, which makes the thermal transfer sheet inoperable or, in extreme cases, from the sticking part. The base film may break. Therefore, a method of providing a heat-resistant protective layer on the back surface of the substrate film has been proposed, for example, a method of providing a silicon oxide layer (see JP-A-54-143152 and JP-A-57-74195), Alternatively, a method of providing a layer of a heat resistant resin such as a silicone resin, an epoxy resin, a melamine resin or a phenol resin (JP-A-55)
-7467, Japanese Patent Laid-Open No. 56-155794). However, the method of providing a heat-resistant protective layer on the back surface of the substrate film requires a large amount of heat energy for thermosetting, requires long-term aging to obtain sufficient heat resistance, There are drawbacks such as insufficient slipperiness for smooth running. There is also known a method of providing a resin layer containing a surfactant on the back surface of the substrate film (see Japanese Patent Laid-Open No. 56-155794), but this has a drawback that contaminants adhere to the thermal head. is there. Therefore, a method of providing a vinyl polymer layer in which organopolysiloxane units are bonded in a block or graft form on the back surface of the substrate film (see JP-B-4-73391 and JP-A-62-121093). ) Has been proposed, but the anti-sticking property and the slip property are not sufficient, and in this method, a solvent-diluting type treating agent is mainly used, which causes environmental and safety problems.

In the case of a magnetic tape in the field of video, for example, the magnetic tape travels in a circuit while being rubbed by guide pins or guide rolls when recording or reproducing an image. Not only the front surface but also the back surface needs to be slippery. Therefore, a method of providing a resin layer containing an inorganic powder on the back surface of the substrate film
57-130234, JP-A-58-161135, JP-A-57-53825
No. 58, JP-A-58-2415, JP-B No. 50-3927), a method for providing a resin layer containing a silicone resin powder (refer to JP-A-62-202325), silicone oil, graphite, fatty acid. Methods of providing a layer containing ester are known, but those using powder will scrape the guide pins, etc., and those using graphite will easily stick, silicone oil,
Those using a fatty acid ester have problems of sticking of magnetic tape and adhesion of dirt to guide pins and the like, and sufficient slipperiness cannot be obtained by these methods.

[0004]

In view of the above situation, the present invention provides a plastic film such as a base film with a slip property and an anti-fusing property, has excellent adhesion to a base material, and has a migration property. The present invention is intended to provide an aqueous surface treatment agent capable of forming a cured film having no (contaminating property).

[0005]

Means for Solving the Problems The present invention has solved the above-mentioned problems, and the gist of the present invention is: 1) a unit represented by the general formula R ¹ ₂ SiO _2/2 as a first component and a general formula Aqueous dispersion of non-fluidic branched silicone having a unit represented by the formula R ¹ SiO _3/2 (wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms) as a constituent unit. Liquid, 2) General formula R ² R ³ N (CH ₂ ) _a [NR ⁴ (CH ₂ ) _b ] _c S as the second component
A dialkoxysilane represented by iR ⁵ (OR ⁶ ) ₂ (here, R ² ,
R ³ and R ⁴ are each a hydrogen atom, or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ⁵ and R ⁶ are each 1 to 6 carbon atoms.
An unsubstituted or substituted monovalent hydrocarbon group of a, b, c is 1
≦ a ≦ 6, 1 ≦ b ≦ 6, 0 ≦ c ≦ 3) an aqueous dispersion of a hydrolyzed condensate, 3) a water-based urethane resin as a third component, and 3 effective components. Component weight ratio is first
Component / second component / third component = 9 to 90% by weight / 0.1 to 40% by weight / 9 to 90% by weight in the surface treatment agent for plastic films. The present invention will be described in more detail below.

The surface treating agent of the present invention comprises the above-mentioned first to third components.
It is an aqueous dispersion (aqueous emulsion) obtained by mixing the components.
The first component is an aqueous dispersion of a non-flowing branched silicone (aqueous emulsion), which has the general formula 1 R ¹ ₂ SiO _2/2 ... The siloxane unit represented by (1) and the siloxane unit represented by the general formula 2 R ¹ SiO _3/2 (2) are used as constitutional units. R ¹ in the general formula is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms. As R ¹ , a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a dodecyl group,
Alkyl group such as tetradecyl group, hexadecyl group, octadecyl group, alkenyl group such as vinyl group, allyl group, aryl group such as phenyl group, tolyl group, cycloalkyl group such as cyclohexyl group, or bond to carbon atom of these groups Examples thereof include a group in which some or all of the hydrogen atoms are substituted with a halogen atom or an organic group containing an epoxy group, a carboxyl group, an amino group or the like.

Such non-flowable branched silicone aqueous emulsions can be prepared by emulsion polymerization. The silicone material for introducing the siloxane units represented by the general formula 1, wherein ^{_{[R 1 2 SiO] A (}} A = 3~
7), a cyclopolysiloxane represented by the formula 7), or a formula R ⁷ O [R ^{1
_{2 SiO] B R 7, HO}} [R 1 2 SiO] B H ( wherein R ⁷ is a methyl group, an ethyl group, a propyl group, a butyl group, an alkyl group such as hexyl group, a cyclopentyl group, a cycloalkyl such as cyclohexyl group Group, phenyl group, halogenoalkyl group such as trifluoropropyl group, and the like, a monovalent hydrocarbon group having 1 to 6 carbon atoms or a halogenated hydrocarbon group, and particularly preferably a methyl group or an ethyl group, and B is A diorganopolysiloxane represented by the formula R ¹ Si (OR ⁷ ) ₃ is used as the silicone raw material for introducing the siloxane unit represented by the general formula 2. For example, it can be easily obtained by emulsifying and dispersing these in water using an emulsifier, adding a catalyst to the mixture to cause a polymerization reaction, and deactivating the catalyst after the polymerization.

The emulsifier used in this emulsion polymerization is not particularly limited, and examples thereof include cationic emulsifiers such as quaternary ammonium salts and alkylamine salts, amphoteric ionic emulsifiers such as alkyl betaines, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl ethers. Nonionic emulsifiers such as oxyethylene alkyl phenyl ether, sorbitan fatty acid ester, glycerin fatty acid ester, etc., organic sulfonic acid, acidic anionic emulsifier such as alkyl sulfate ester, etc.
One or two or more of these can be used.

When a cationic emulsifier, a zwitterionic emulsifier or a nonionic emulsifier is used as the polymerization catalyst, potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium methylate, ammonia, Examples thereof include alkali compounds such as tetramethylammonium hydroxide, triethylamine and triethanolamine. Acidic anionic emulsifiers such as organic sulfonic acids and alkyl sulfates have a catalytic action as they are.
For the deactivation of this catalyst, in the case of an alkaline compound catalyst, a method of neutralizing with an acid such as acetic acid, phosphoric acid, hydrochloric acid or citric acid can be mentioned. When an acidic anionic emulsifier is used as a catalyst, it is neutralized with an alkaline compound such as potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium methylate, ammonia, tetramethylammonium hydroxide, triethylamine, triethanolamine. There is a method of doing.

If the concentration of the active ingredient in the aqueous emulsion produced in this way is less than 1% by weight, it becomes uneconomical because the amount of the active ingredient to be blended must be increased. If it is larger than this, the viscosity of the first component becomes high and handling becomes difficult. Therefore, the range is 1 to 70% by weight, and the preferable range is 10 to 60% by weight.

The second component is the hydrolysis of the dialkoxysilane containing an aminoalkyl group represented by the general formula R ² R ³ N (CH ₂ ) _a [NR ⁴ (CH ₂ ) _b ] _c SiR ⁵ (OR ⁶ ) _2. It is an aqueous dispersion of the condensate. R ² , R ³ in the formula,
R ⁴ is a hydrogen atom or an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group, a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a halogenoalkyl group such as a trifluoropropyl group and a phenyl group. It is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, the hydrogen atom of which is 90 mol% or more,
The hydrocarbon group is preferably 10 mol% or less. R ⁵ and R ⁶ are
It is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms similar to R ² , R ³ and R ^4, and is particularly preferably a methyl group or an ethyl group. Regarding a, b, and c, a and b are 0
In the case of the above, the target hydrolysis-condensation product cannot be obtained because the Si-N bond is hydrolyzed, and if it is larger than 6, the effect of improving the adhesiveness with the surface of the plastic film as the characteristic effect of the second component decreases. 1 ≦ a ≦ 6, 1 ≦ b ≦ 6, preferably a and b are 2 or 3, and when c is greater than 3, industrial synthesis is difficult, and thus 0 ≦ c ≦ 3.
It is said that.

Examples of the aminoalkyl group-containing dialkoxysilane include γ- (N-β-aminoethyl) aminopropylmethyldimethoxysilane, γ- (N-β-aminoethyl) aminopropylmethyldiethoxysilane, and γ.
Typical examples include -aminopropylmethyldimethoxysilane and γ-aminopropylmethyldiethoxysilane. The hydrolysis of these silanes may be carried out according to a known method. Since the dealcoholization condensation reaction of these silanes easily proceeds when water is added to these silanes, the produced alcohol may be distilled off thereafter.

When this dialkoxysilane hydrolyzate is mixed with water, it is easily dissolved or dispersed in water to form a uniform aqueous dispersion. The amount of dialkoxysilane in the aqueous dispersion of the second component is If this is less than 1% by weight,
It is uneconomical because the amount of this compounded must be increased, and if it exceeds 50% by weight, the viscosity of the liquid will increase and it will be difficult to uniformly disperse it with other components. The preferred range is from 10 to 30% by weight, although the preferred range is from -50% by weight. In addition,
In order to improve the homogeneity of the aqueous dispersion of this second component,
In order to improve the liquid stability when the first to third components are mixed, organic acids such as formic acid, acetic acid, propionic acid, malonic acid, maleic acid, salicylic acid, hydrochloric acid, phosphoric acid, sulfuric acid, etc. The addition of the above inorganic acid is the preferred method.

The third component is an aqueous urethane resin, which is a urethane resin which is a reaction product of a polyisocyanate and a polyhydroxy compound dissolved in water or emulsified and dispersed in water. There are no particular restrictions on the polyisocyanate that is the raw material for this urethane resin. Similarly, the polyhydroxy compound which is a raw material is not particularly limited, and may be any type such as ester type, ether type and carbonate type. Further, the urethane resin may be a non-reactive type that does not contain an active isocyanate group or a reactive type that contains an active isocyanate group. Water-based urethane resin has a breaking elongation of 300% at room temperature or by heating and drying.
If it is larger than 5%, the cured film is too soft and falls off due to friction. If it is less than 5%, the cured film becomes too hard and it is difficult to follow the deformation of the coated plastic film. . It is more preferably 10 to 200%. If the effective component concentration of the water-based urethane resin is less than 1% by weight, it becomes uneconomical because the amount of the compounded compound must be increased.
If it is more than 10% by weight, the viscosity of the third component becomes high and it becomes difficult to handle. Therefore, it may be set in the range of 1 to 70% by weight, but the preferable range is 10 to 60% by weight.

With respect to the compounding ratio of the above-mentioned first to third components, when the amount of the active ingredient of the first component in the total of the active ingredients of these components is less than 9% by weight, the slipperiness of the cured film becomes poor, and 90% by weight. If it is more, the hardness of the cured film will decrease and it will come off due to friction. If the amount of the active ingredient of the second component is less than 0.1% by weight, the curability of the film will decrease, and the first component will contact other contact surfaces. The problem of migration also occurs, and if it exceeds 40% by weight, the slipperiness of the cured film becomes poor, and the third
If the effective amount of the component is less than 9% by weight, the hardness of the cured film will be reduced and will come off due to friction. If it exceeds 90% by weight, the heat resistance will be poor and the slipperiness of the cured film will be poor. Therefore, these compounding ratios are such that the amount of the active ingredient is the first component / second component / third component = 9 to 90% by weight / 0.1 to 40%.
% / 9 to 90% by weight is necessary,
The first component / second component / third component = 19 to 80% by weight / 0.2 to 20% by weight / 19 to 80% by weight is preferable.

When the concentration of the active ingredient in the aqueous emulsion containing the first to third components is less than 1% by weight, the cured film becomes thin and the slipperiness becomes poor. Since the viscosity of the emulsion becomes high and coating becomes difficult, it is preferable to set it in the range of 1 to 50% by weight, but it is preferable to set it to 5 to 30% by weight, and if necessary dilute with water. Good. In addition, in order to increase the strength and curability of the film, a mixture of the above-mentioned first to third components may be a trialkoxysilane containing an epoxy group, a methacryl group, an amino group or a mercapto group, an epoxy group, a methacryl group or It is optional to add a hydrolysis-condensation product of a dialkoxysilane containing a mercapto group. In addition, in order to accelerate the curing of the film, the above mixture may be mixed with an organic acid metal salt such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, tin octylate, iron octylate, or zinc octylate. Is optional.

Examples of the plastic film to be treated with the surface treating agent of the present invention, which is an aqueous emulsion containing the above-mentioned first to third components, include films of polyester, polypropylene, cellulose derivative, polyamide, polycarbonate and the like. . The surface treatment of the plastic film is performed by applying the surface treatment agent of the present invention by a coating method such as a roll coating method, a gravure coating method, a screen coating method or a fountain coating method, and then curing the film by room temperature or heating drying. . The plastic film thus treated is preferably used as a heat-sensitive sheet or a base sheet of a magnetic tape with the treated surface as the back surface.

[0018]

EXAMPLES The present invention will be described more specifically below with reference to examples. In the examples,% means% by weight and part means part by weight. (Preparation Example 1, Preparation of First Component-1) 350 g of octamethylcyclotetrasiloxane, phenyltriethoxysilane 1.
3 g was charged into a 1 liter glass beaker, and stirred and mixed at 2,000 rpm with a homomixer, 10% sodium lauryl sulfate aqueous solution 35 g and 10% dodecylbenzenesulfonic acid aqueous solution 35 g were added, and stirring was continued at 6,000 rpm,
Phase inversion occurred and thickening was observed, but further 2,000r
Add 280g of water while stirring at pm, then 300kg / c
Stable O / W when passed through a m ² high pressure homogenizer
A type emulsion was obtained.

Next, this emulsion was transferred to a glass flask having a volume of 1 liter equipped with a stirrer, a thermometer and a reflux condenser, reacted at 50 ° C. for 12 hours, and then aged at 25 ° C. for 24 hours, then 10 % Aqueous solution of sodium carbonate to obtain an aqueous emulsion containing a branched silicone (hereinafter referred to as the first component-1). Isopropyl alcohol was added to the emulsion to destroy the emulsion. The siloxane was extracted and dried to obtain a gel-like non-fluidic siloxane. This active ingredient is 49%.

(Preparation Example 2, Preparation of Second Component-1) γ-
500 g of (N-β-aminoethyl) aminopropylmethyldimethoxysilane was charged into a glass flask having a capacity of 1 liter equipped with a stirrer, a dropping device, a thermometer and a reflux condenser, and 135 g of deionized water was stirred at room temperature. After dropping for 30 minutes, the reaction system was depressurized while raising the temperature after the dropping, and the produced methanol was distilled off. Then, after continuing the depressurization operation at 55 to 60 ° C. for 30 minutes, the reaction was terminated by cooling and returning to normal pressure to obtain the hydrolyzed condensate 10.
5 g of water was charged into a 1 liter glass flask charged with 595 g of water at room temperature and stirred for 30 minutes to obtain this aqueous dispersion (hereinafter referred to as second component-1). The content of the active ingredient in this product is 15%.

(Preparation Example 3, Preparation of Second Component-2) 500 g of γ-aminopropylmethyldimethoxysilane was stirred,
A glass flask with a capacity of 1 liter equipped with a dropping device, a thermometer, and a reflux condenser was charged, and 170 g of deionized water was added dropwise over 30 minutes with stirring at room temperature. After completion of the dropping, the reaction system was depressurized while raising the temperature, and the produced methanol was distilled off,
After continuing the depressurization operation at 55-60 ° C for 30 minutes, the reaction was terminated by cooling and returning to normal pressure to terminate the reaction, and 105 g of the obtained hydrolyzed condensate was placed at room temperature in a 1-liter glass flask charged with 595 g of water. After being charged and stirred for 30 minutes, this aqueous dispersion (hereinafter referred to as the second component-2) was obtained. The content of the active ingredient in this product is 15%.

(Examples 1 to 8) The first component and the second component obtained in the preparation example and the third component described below were mixed in the composition shown in Table 1 to prepare a surface treatment agent composition. Was applied to the surface of a polyethylene terephthalate film (thickness: 0.5 mm) with a No. 3 wire bar, and left in a hot air circulation type constant temperature bath controlled at 140 ° C for 1 minute to form a cured film on the surface of the film. Then, the surface-treated film thus obtained was evaluated for surface slipperiness, adhesion and migration by the following methods. The results are as shown in Table 1.

A. Evaluation of surface slipperiness Evaluation was performed by applying a load of 220 g to a glass plate having a size of 40 mm × 70 mm and measuring a dynamic friction coefficient under a condition of a tensile speed of 200 mm / min. b. Evaluation of Adhesion The surface of the film was strongly rubbed with a finger, and the presence or absence of the cured film was visually observed. In the evaluation, those with no rubbing marks and no film loss were evaluated as ◯, those with rubbing marks were evaluated as Δ, and those with no film removal were evaluated as x. c. Evaluation of transferability After the untreated film and the treated surface of the treated film were overlapped with each other and held at a pressure of 10 kg / cm ² for 1 day, the untreated film was widened on the surface that was in contact with the treated film. It was applied with a marker and the ink repellency was observed. In the evaluation, those without repellency were evaluated as ◯, and those with repellency were evaluated as x. As seen in Table 1, all of them showed excellent results in terms of surface slipperiness, adhesion and migration.

[0024]

[Table 1]

Comparative Examples 1 to 4 The surface treatment agent compositions were prepared by mixing the first component and the second component obtained in the preparation example with the above-mentioned third component in the composition shown in Table 2. The surface treatment of the film was carried out in the same manner as in Examples using the above, and the obtained surface-treated film was similarly evaluated for surface slipperiness, adhesion and migration, and the results as shown in Table 2 were obtained. was gotten. As seen in the table,
None of these examples satisfied surface slipperiness, adhesion and migration at the same time.

[0026]

[Table 2]

[0027]

EFFECTS OF THE INVENTION The aqueous surface treatment agent of the present invention can form a cured film having excellent slipperiness, anti-fusion property and adhesiveness and no migration property on a plastic film. Since the surface treating agent of the present invention is aqueous, there is no problem in environmental influence and safety. The plastic film treated with the surface treating agent of the present invention is suitable for use as a heat-sensitive sheet or a base sheet of a magnetic tape with the treated surface as the back surface.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 83/04 LRU C09D 175/04 PHX 183/04 PMT PMU // B42D 15/10 501 A (72) Inventor Satoshi Kuwata No. 1 Hitomi, Osaka, Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (1)

[Claims] 1. A unit represented by the general formula R ¹ ₂ SiO _2/2 as a first component and a unit represented by the general formula R ¹ SiO _3/2 (wherein R ¹ has 1 to 20 carbon atoms). An aqueous dispersion of a non-fluidic branched silicone having an unsubstituted or substituted monovalent hydrocarbon group) as a constituent unit, 2) a general formula R ² R ³ N (CH ₂ ) _a [NR ⁴ (CH ₂ ) _b ] _c S
A dialkoxysilane represented by iR ⁵ (OR ⁶ ) ₂ (here, R ² ,
R ³ and R ⁴ are each a hydrogen atom, or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ⁵ and R ⁶ are each 1 to 6 carbon atoms.
An unsubstituted or substituted monovalent hydrocarbon group of a, b, c is 1
≦ a ≦ 6, 1 ≦ b ≦ 6, 0 ≦ c ≦ 3) an aqueous dispersion of a hydrolyzed condensate, 3) a water-based urethane resin as a third component, and 3 effective components. Component weight ratio is first
Component / second component / third component = 9 to 90% by weight / 0.1 to 40% by weight / 9 to 90% by weight, surface treatment agent for plastic film.