JP2590107B2 - Thermal release agent - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a release agent, and more particularly, to a thermal release agent having excellent release properties even in a wide temperature range, particularly under heating.

[Background of the Invention]

Conventionally, as a release agent used for producing a molded article such as a plastic, for example, silicone resin, various waxes, stearate salts, tetrafluoroethylene resin, and the like have been widely used. These release agents are used by being added to a polymer to be molded or applied to a mold. In addition, when attention is paid to the use form or properties of the release agent, for example, it is used as an oil-type release agent, a paste-type release agent, an aerosol-type release agent, a solution-type release agent, or an emulsion-type release agent. Have been. Furthermore, what is generally known as release paper can be obtained by applying and curing a silicone resin on the surface of a base paper.

By the way, the above-mentioned conventional release agent is sufficiently effective as a release agent used in, for example, a usual plastic molding process using a mold. When used for the purpose of imparting properties, it is not always sufficiently satisfactory. That is, for example, in a technique of forming an image by a thermal transfer method, a desired image is formed on the image receiving sheet by superimposing a thermal transfer sheet having a dye layer and an image receiving sheet (heat receiving sheet) and heating and printing with a thermal head. The releasability is one of the important characteristics required for each of the sheets used in this case. In other words, since the thermal transfer sheet and the image receiving sheet are superimposed and heated as described above, it is important that both sheets have excellent releasability (or ease of peeling) after printing in order to smoothly perform image formation. Further, since each sheet is usually used before and after printing, it is an important characteristic that the releasability should be provided in preventing blocking between the sheets. In addition to the sheet-like products as described above, there are also products such as various kinds of painted products, which require particularly good releasability (non-adhesion) on the surface.

However, the products using the conventional release agents as described above have the following problems.

(A) In the thermal transfer sheet and the image receiving sheet as described above, each sheet is instantaneously exposed to a high temperature during the heating and printing by the thermal head. In a sheet using a conventional release agent, such a sheet is used. The releasability at the time of applying high energy is not always satisfactory, and has disadvantages such as heat fusion at a printed portion or inevitable undesired mass transfer between opposing sheet surfaces.

(B) Conventionally, when a release property is imparted to a synthetic resin sheet product or a coated product as described above, a method of adding a release agent such as silicone to a raw material polymer is usually employed.
Conventional release properties generally do not have good compatibility with the raw material polymer.Therefore, after the preparation of the raw material composition or after the formation of the coating film, the release agent component undergoes phase separation and flows or migrates, or the surface of the product can be removed. There is a problem in that various adverse effects are caused, such as deterioration of the layer with time and deterioration of the releasability due to the emergence of the layer.

(C) In the case of a conventional release agent, when a resin layer or a coating film having releasability is formed on a certain base material, the base material and the formation layer are necessarily formed due to the release agent to be added. The adhesiveness between the substrates must be reduced, so that excellent release properties on the surface of the forming layer and the so-called mutually contradictory characteristics of the adhesiveness between the base material and the forming layer are imparted. In, conventional release agents are not satisfactory.

[Summary of the Invention]

The present invention has been made in view of the above-mentioned problems of the prior art, and has excellent release properties over a wide temperature range, has excellent compatibility with a polymer to be added, and has been further obtained. It is an object of the present invention to provide a heat release agent having an excellent effect in improving the stability over time and the storage stability of a product.

In order to achieve the above object, a thermal release agent according to the present invention is characterized in that a polymer having an organopolysiloxane component in a main chain or a side chain of the polymer is contained as a main component.

[Specific description of the invention]

Hereinafter, the thermal release agent according to the present invention will be described in more detail.

In the following description,% representing a quantitative ratio is based on weight unless otherwise specified.

The thermal release agent according to the present invention basically comprises a polymer having an organopolysiloxane represented by the following general formula in the main chain or side chain of the polymer.

In the above formulas, R, R 'is a methyl group, an ethyl group, an alkyl group such as propyl, or an aryl group such as phenyl _{group, -OH, -NH 2, -NH -} , - COOH, epoxy It may contain a functional group such as a group. R and R 'may be the same or different. Further, n is preferably an integer in the range of 8 to 120.

In the heat release agent of the present invention, depending on the purpose,
Other additives such as a binder, a dye, a pigment, a surfactant, and an antioxidant can be used in combination.

Hereinafter, the heat release agent will be described in two types, that is, a main chain type and a side chain type, focusing on the bonding position of the organopolysiloxane to the basic skeleton of the polymer.

Main chain type As the main chain type, for example, those in which the basic skeleton of the polymer is made of polyester, polyurethane or polyamide are preferably used. Specifically, it is a polymer as shown below.

In the above formula, R ₁ , R ₂ , R ₃ and R ₄ each have 4 to 30 groups.
Is a methylene group or a phenyl group in general,
The following bisphenols may be used.

In the formula of the main chain polymer, the bond (I)
And (II) each represent an ester bond when the basic skeleton is a polyester, a urethane bond when a polyurethane is used, and an amide bond when the basic skeleton is a polyamide.

The main chain type heat releasing polymer having the above structure is a silicone-modified polymer containing an organopolysiloxane component in the main chain. The amount of silicone modification in the polymer is preferably 3 to 50%, more preferably 5 to 30% based on the total weight of the polymer. If the amount of silicone modification is less than 3%, the heat releasing effect is insufficient, while 50%
If it exceeds, it is not preferred because gelation occurs at the time of polymerization, or the polymerization lacks uniformity, and it becomes difficult to obtain a transparent polymer.

The molecular weight of these silicone-modified polymers is 50
00 to 50000, and the degree of polymerization is preferably about 10 to 100.

Next, a method for synthesizing the main chain polymer will be described.

Silicone-modified polyester Usually, it can be synthesized by polycondensation of a diol component having a primary alcoholic hydroxyl group at both ends of an organopolysiloxane as described below and a dicarboxylic acid component.

Dialkyl polysiloxane modified diol: In the above formula, n is an integer in the range of 8-120.

Dicarboxylic acid component: HOOC-R-COOH In the above formula, R is a methylene group (the number of methylene groups is 4 to 30).
Or a phenyl group.

The silicone-modified polyester can be synthesized by polymerization of the above-mentioned dialkylpolysiloxane component and dicarboxylic acid component, and may appropriately contain the following diol components in addition to the above two components. As such a diol component, a component having a phenyl group, such as bisphenol A, bisphenol B, bisphenol AF, and bisphenol S, or a component having no phenyl group may be used.

In synthesizing the polymer, each of the components may be a single type or a mixed type of a plurality of types.

Silicone-modified polyurethane Usually, a diol component having a primary alcoholic hydroxyl group at both ends of the organopolysiloxane as described above,
It can be synthesized by a polyaddition reaction with the following diisocyanate.

Diisocyanates: Diisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), and isophorone diisocyanate (IPDI).

The silicone-modified polyurethane can be synthesized by polymerization of the dimethylpolysiloxane component and the diisocyanate component. In addition to the two types of components, the same diol component as described in the description of the silicone-modified polyester is used. obtain.

Silicone-Modified Polyamide Usually, it can be synthesized by polycondensation of a diamine component having a primary amino group at both ends of an organopolysiloxane and a dicarboxylic acid component as described below.

Dialkyl polysiloxane modified diamine: In the above formula, n is an integer in the range of 8-120.

Dicarboxylic acid component: HOOC-R-COOH In the above formula, R is a methylene group (the number of methylene groups is 4 to 30).
Or a phenyl group.

Further, the silicone-modified polyamide in this case can also be synthesized by polycondensation of a dicarboxylic acid component having a carboxyl group at both terminals of a dimethylpolysiloxane and a diamine component as shown below.

Dialkyl polysiloxane modified dicarboxylic acid: In the above formula, n is an integer in the range of 8-120.

Diamine component: H ₂ N—R—NH _{2 In the} above formula, R is a methylene group (the number of methylene groups is 2 to 12).
Or a modified diamine containing a phenyl group or O, S or the like.

Further, the silicone-modified polyamide can be synthesized by the above-described two-component polymerization, but in the synthesis, each component may not be a single component, and for example, a plurality of types of components may be appropriately mixed and used. it can.

Side-chain type polymer The side-chain type polymer has an organopolysiloxane component in the side chain of the basic skeleton of the polymer. A silicone graft copolymer obtained by copolymerizing a macromonomer (macromer) with an ethylenically unsaturated monomer such as an acrylic or vinyl monomer by applying the side chain type polymer to the synthesis method.

As the silicone macromonomer, for example, the following can be used.

The classification is as follows.

(1) Silicone having (meth) acrylic group In the above formula, n is an integer in the range of 5-120.

(2) A silicone-modified polymer obtained by reacting a previously obtained polymer with a silicone compound to pend the silicone.

For example, a hydroxyl group, a carboxyl group,
By reacting a silicone compound having a carboxyl group, a hydroxyl group, an amino group, an epoxy group, or an isocyanate group at the terminal with the reactive group of the polymer having a reactive group such as an amino group or an epoxy group, silicone is formed into a side chain of the polymer. Can be pendant. Specifically, a combination of the following two reactive groups can be considered. Polymeric silicone hydroxyl group Carboxyl group Hydroxyl group Isocyanate group Carboxyl group Hydroxyl group Carboxyl group Amino group Carboxyl group Epoxy group Amino group Carboxyl group Amino group Epoxy group Epoxy group Carboxyl group Epoxy group Amino group It is obtained by the above method (1) or (2). The side-chain type heat-releasing polymer is a silicone-modified polymer characterized by containing a dimethylpolysiloxane component in a side chain. In this case, the silicone modification amount is preferably 5 to 70%, more preferably 10 to 70% based on the total amount of the polymer.
~ 50%. If the silicone modification amount is less than 5%, the heat releasing effect is insufficient, while if it exceeds 70%, on the contrary, thickening and gelation occur during polymerization and reaction, and high transparency cannot be obtained. It is not preferable. The molecular weight of these silicone-modified polymers is preferably in the range of 5,000 to 50,000.

Function / Effect As described above, the thermal release agent according to the present invention is composed of a polymer having an organopolysiloxane component in the main chain or side chain of the polymer, and therefore has the following excellent properties.

(A) Thermal release properties Excellent release properties in a wide temperature range, particularly under high-temperature heating, and therefore exhibit excellent effects as thermal release agents for various sheets for image formation by a thermal transfer system. In particular, it is possible to solve the problem of heat fusion associated with heating printing.

In addition, it is suitable as a release agent for a polymer composition for molding requiring surface release properties, or as a release polymer such as release paper.

(B) Lubricity Silicone has an excellent effect of reducing friction as a function of silicone, and is effective as a polymer for imparting lubricity. (C) Water repellency (oil repellency) Increases the contact angle of the surface It has the effect of remarkably improving water repellency and oil repellency, so that it imparts stain resistance to products and is effective as a frost damage prevention material and a graffiti prevention coating material.

(D) Compatibility Since the silicone component in the heat release agent has a structure bonded to the polymer that is the basic skeleton, even when added as a compounding component to another polymer composition, the Phase separation and other problems that occur when a silicone resin alone is added to a rubber.

(E) Adhesion The basic structure other than the silicone component of the polymer constituting the heat release agent contributes to the improvement of the adhesion (adhesion) to the base material. Things.

(G) Silicone stain resistance When added to a specific polymer composition, in a conventional release agent (for example, silicone), the release agent component may have various adverse effects on other products. For example, a thermal transfer sheet and an image receiving sheet are usually stacked or stored in a roll state. However, in a conventional release agent, there is a problem that a blocking phenomenon easily occurs between the sheets due to the release agent component. Was. However, in the thermal release agent of the present invention, since the silicone component is bonded to the skeletal polymer, the above-mentioned problem of contamination caused by the silicone component itself is solved.

(H) High molecular weight Since the heat release agent itself has a large molecular weight, it is advantageous in terms of strength, has excellent weather resistance, and is formed as a coating film on another substrate. It also has an excellent effect on film formability in such cases. Therefore, the thermal release agent of the present invention is advantageous in this point and in the above point (d).
It has an excellent effect on storage stability and stability over time.

〔Example〕

Hereinafter, the synthesis and test examples of the thermal release agent of the present invention will be described.

Synthesis Example 1 675 g of dimethyl terephthalate, 225 g of dimethyl isophthalate (mixing ratio 75:25), 810 g of ethylene glycol,
1480 g of silicone-modified diol, X-22-160B (manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.81 g of litharge as a catalyst are placed in a three-necked flask, and heated and stirred at 140 to 240 ° C. for 3.5 hours while introducing N ₂ . After all of the methanol has been distilled off, the pressure is reduced to 10 mmHg and excess glycol is distilled off. Then, 1mmH
g was further reacted at 270 ° C. for 9 hours under reduced pressure to increase the molecular weight to obtain a silicone-modified polyester.

Synthesis Example 2 54 g of 1,4-butanediol, silicone-modified diol,
100 g of Thyraplane FM4411 (manufactured by Nippon Steel Co., Ltd.) and 154 g of methyl ethyl ketone (MEK) as a solvent are placed in a three-necked flask, and 0.3 g of dibutyltin dilaurate is added and stirred well. Next, a solution in which 133 g of diphenylmethane diisocyanate was dissolved in 133 g of MEK was appropriately mixed, and the mixture was heated and stirred for 5 hours while adjusting the mixed reaction solution so as not to be 80 ° C. or higher, to obtain a silicone-modified polyurethane.

Synthesis Example 3 5.8 g of hexamethylene diamine, silicone-modified diamine, 10 g of Silaprene FM3311 (manufactured by Nippon Steel), 0.10 g of surfactant Emulgen 106 (manufactured by Kao Corporation), and 110 g of water were well emulsified and dispersed in a flask. Triethylamine 12
Add g and allow to cool with ice. Then, 11 g of adipic acid chloride is dissolved in 44 g of toluene, and cooled similarly. The cooled diamine solution is poured into a reaction vessel of a homomixer for interfacial polymerization, and then the acid chloride solution is gently poured to form an interface, and the surroundings are cooled with ice. Then, the mixture was rotated at a high speed with a homomixer to perform interfacial polymerization.
The produced polymer was thoroughly washed with water and dried.

Synthesis Example 4 A three-necked flask was charged with 375 g of a mixed (1: 1) solution of methyl isobutyl ketone and ethyl acetate, and while introducing N ₂ ,
Reflux in a warm bath. Subsequently, 25 g of 2-hydroxyethyl acrylate, 125 g of methacrylic acid methyl ester, silicone-modified acrylic, 100 g of Silaplane FMO711 (manufactured by Nippon Steel), α, α′-azobisisobutyronitrile 2.
5 g are mixed and dropped into a stirring refluxing solution to perform radical solution polymerization. After completion of the dropwise addition, the mixture was further stirred for 2 hours to obtain a polymer.

Synthesis Example 5 A three-necked flask was charged with 100 g of ethyl acetate, and stirred and refluxed in a warm bath while introducing N ₂ . Then, acrylic acid 30
g and 70 g of methacrylic acid methyl ester were dropped into the reflux solution to perform radical solution polymerization. Next, a mixed solution of 200 g of silicone-modified epoxy on one end, 200 g of Silaplane FMO521 (manufactured by Nippon Steel Co., Ltd.) and 200 g of ethyl acetate is dropped, and a reaction between a carboxyl group and an epoxy group is carried out at 80 ° C. using pyridine as a catalyst. Therefore, stirring was performed for 3 hours to obtain a silicone-modified graft copolymer.

Examples and Comparative Examples Each of the polymers obtained in Synthesis Examples 1 to 5 was coated on PET100μ to a thickness of 10 g / m ² , dried, and then examined for various properties of the coating film. The results are shown in Table 1 below.

Claims (6)

(57) [Claims] 1. A thermal release agent for a thermal transfer sheet, comprising a silicone-modified polymer containing an organopolysiloxane component in a main chain or a silicone-modified polymer containing an organopolysiloxane component in a side chain. . 2. The thermal release agent according to claim 1, wherein the basic skeleton of the polymer comprises polyester. 3. The thermal release agent according to claim 1, wherein the basic skeleton of the polymer comprises polyurethane. 4. The thermal release agent according to claim 1, wherein the basic skeleton of the polymer comprises polyamide. 5. The thermal release agent according to claim 1, wherein the basic skeleton of the polymer comprises a polymer of an ethylenically unsaturated monomer. 6. The thermal release agent according to claim 1, wherein the organopolysiloxane is dimethylpolysiloxane.