JP2654381C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a sheet release agent for image formation by a thermal transfer system, and more particularly, to
The present invention relates to an image forming sheet having excellent releasability even in a wide temperature range, particularly under heating. 2. Description of the Related Art Conventionally, release agents used for producing molded articles such as plastics include, for example, silicone resins, various waxes, stearates, tetrafluoroethylene, and the like. Resins and the like are 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 mold releasability to the rubber, it is not always satisfactory. That is, for example, in the technique of forming an image by a thermal transfer method, a desired image is formed on the image receiving sheet by superposing 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, products using the above-mentioned conventional release agents 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 heating and printing by a thermal head, but in a sheet using a conventional release agent, The releasability at the time of application of such high energy is not always sufficiently satisfactory, and disadvantages such as thermal fusion occurring at a printed portion or undesired mass transfer between the opposing sheet surfaces occur. There is. (B) Conventionally, when a release property is given 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. However, conventional release agents generally do not have good compatibility with the raw material polymer.Therefore, after the preparation of the raw material composition or the formation of the coating film, the release agent component undergoes phase separation to flow, migrate, or There is a problem in that various adverse effects are caused, such as deterioration on the surface layer over time and deterioration of the releasability over time. (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, it is inevitably formed with the base material for the release agent to be added. The adhesion between the layers must be reduced, and therefore, the excellent releasability on the surface of the formation layer and the mutual inconsistency of the adhesion between the base material and the formation layer are combined. Conventional release agents are not satisfactory for application. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has excellent mold releasability over a wide temperature range, and has an advantage over time. An object of the present invention is to provide an image receiving sheet having an excellent effect in improving stability and storage stability. In order to achieve the above object, an image receiving sheet according to the present invention is characterized in that a polymer having an organopolysiloxane component in a main chain or a side chain of a basic skeleton of the polymer is applied as a thermal release agent. Features. Hereinafter, the thermal release agent according to the present invention will be described in more detail. In the following description, percentages expressing quantitative ratios are 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 as a main component. [0013] In the above formula, R and R 'represent an alkyl group such as a methyl group, an ethyl group and a propyl group, or
A aryl group such as phenyl _{group, -OH, -NH 2, -NH -} , - COO
It may contain a functional group such as H or an epoxy 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 thermal release agent according to the present invention, a binder, a dye,
Other additives such as pigments, surfactants and antioxidants may 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. As the main chain type , for example, those in which the basic skeleton of the polymer is made of polyester, polyurethane, polyamide or the like are preferably used. Specifically, it is a polymer as shown below. Embedded image In the above formula, R ₁ , R ₂ , R ₃ , and R ₄ each generally represent a methylene group having 4 to 30 groups or a phenyl group, but may be the following bisphenol. Embedded image In the formula of the main chain polymer, bonds (I) and (II) are
When the basic skeleton is a polyester, it is an ester bond, when it is a polyurethane, it is a urethane bond, and when it is a polyamide, it is an amide bond. 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 silicone modification amount is less than 3%, the heat releasing effect is insufficient, while if it exceeds 50%, gelation occurs at the time of polymerization, the polymerization lacks uniformity, and it becomes difficult to obtain a transparent polymer. . The molecular weight of these silicone-modified polymers is preferably 5,000 to 50,000, and the degree of polymerization is preferably about 10 to 100. Next, a method for synthesizing the main chain type 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 terminals 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-mentioned two components. As such a diol component, a component containing 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 above components may be a single type or a mixed type of a plurality of types. Silicone-modified polyurethane Usually, it can be synthesized by a polyaddition reaction of a diol component having a primary alcoholic hydroxyl group at both terminals of the above-mentioned organopolysiloxane with the following diisocyanate. Diisocyanate: 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 above-mentioned dimethylpolysiloxane component and diisocyanate component. In addition to the above two kinds of components, the same diol component as described in the description of the above-mentioned silicone-modified polyester is used. Can be used. Silicone-Modified Polyamide Usually, it can be synthesized by polycondensation of a diamine component having a primary amino group at both terminals of an organopolysiloxane as described below and a dicarboxylic acid component. A dialkylpolysiloxane-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. Dialkylpolysiloxane-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), a phenyl group, or a modified diamine containing O, S, or the like. It is. The silicone-modified polyamide can be synthesized by the above-described two-component polymerization. However, at the time of synthesis, each component need not be a single component. For example, a plurality of types of components may be appropriately mixed and used. can do. 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 attaching the side chain type polymer to the synthesis method. As the silicone macromonomer, for example, the following can be used. Embedded image 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 silicone compound with a previously obtained polymer to pendant the silicone. For example, in a polymer having a reactive group such as a hydroxyl group, a carboxyl group, an amino group, or an epoxy group on the skeleton of the main chain, a carboxyl group, a hydroxyl group, an amino group, an epoxy group, an isocyanate The silicone can be pendant to the side chain of the polymer by reacting a silicone compound having a group. 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 The above methods (1) and (2) Is a silicone-modified polymer characterized by containing a dimethylpolysiloxane component in the side chain. In this case, the silicone modification amount is 5 to 5% based on the total amount of the polymer.
It is preferably 70%, more preferably 10 to 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 or gelation occurs during polymerization or reaction, and high transparency cannot be obtained. It is not preferable. The molecular weight of these silicone-modified polymers is from 5,000 to 500
A range of 00 is preferred. Function / Effect As described above, the image-receiving sheet according to the present invention is obtained by applying a thermal release agent composed of a polymer having an organopolysiloxane component in the main chain or side chain of the polymer.
It has the following excellent properties. (B) Thermal releasability The releasability is excellent over a wide temperature range, particularly under high-temperature heating, and therefore, it exhibits an excellent effect as an image receiving sheet by a thermal transfer system. In particular, it is possible to solve the problem of heat fusion associated with heating printing. (B) Lubricity Since an excellent effect of reducing friction is exhibited as an effect of silicone, an image receiving sheet having good slipperiness can be obtained. (C) Water repellency (oil repellency) Since it has the effect of increasing the contact angle of the surface and remarkably improving the water repellency and oil repellency, it is possible to obtain an image receiving sheet having excellent stain resistance. (D) Compatibility Since the silicone component in the applied heat release agent has a structure bonded to the polymer that is the basic skeleton, even if it is added as a compounding component to another polymer composition, As described above, phase separation and other problems that occur when a silicone resin is added alone are unlikely to occur. The basic structure other than the silicone component of the polymer constituting the (e) adhesion NetsuHanare agent is, since the contribution to the improvement of adhesion to the substrate (adhesion), the image receiving sheet also excellent characteristics in this respect < can be obtained. (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 present invention has an excellent effect in this point and in the above point (d) in storage stability and stability over time. EXAMPLES Hereinafter, synthesis examples 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, silicone-modified diol, X-
22-160B (Shin-Etsu Chemical Co., Ltd.) 1480 g, Lisage 0.81 as a catalyst
g in a three-necked flask, and heated and stirred at 140 to 240 ° C. for 3.5 hours while introducing N ₂ . After all the methanol has been distilled off, the pressure is reduced to 10 mmHg, and the excess glycol is distilled off. Subsequently, the pressure was further reduced to 1 mmHg, and the reaction was carried out at 270 ° C. for 9 hours to increase the molecular weight to obtain a silicone-modified polyester. Synthesis Example 2 54 g of 1,4-butanediol, silicone-modified diol, Silaprene F
100 g of M4411 (manufactured by nitrogen), methyl ethyl ketone (MEK) as solvent
Put 154 g in a three-necked flask, add 0.3 g of dibutyltin dilaurate, and stir well. Next, 133 g of MEK was added to 133 g of MEK.
g was dissolved under appropriate conditions, and the mixture was heated and stirred for 5 hours while adjusting the temperature of the mixed reaction solution to 80 ° C. or higher to obtain a silicone-modified polyurethane. Synthesis Example 3 5.8 g of hexamethylenediamine, silicone-modified diamine, 10 g of Silaprene FM3311 (manufactured by Nippon Steel), surfactant Emulgen 106 (manufactured by Kao Corporation)
0.10 g and 110 g of water are well emulsified and dispersed in a flask, then 12 g of triethylamine is added, and the surrounding is cooled with ice. And adipic acid chloride 11
g 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 In a three-necked flask, 375 g of a mixed (1: 1) solution of methyl isobutyl ketone and ethyl acetate was put, and refluxed in a warm bath while introducing N ₂ . Then, 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 Co., Ltd.), α
, Α'-azobisisobutyronitrile are mixed and dropped into the stirring refluxing solution to carry out 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 30g, methacrylic acid methyl ester 70g
Was dropped into the reflux solution to perform radical solution polymerization. Next, a mixed solution of 200 g of silicone-modified one-terminal epoxy, 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 performed 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 The polymers obtained in Synthesis Examples 1 to 5 were each coated on PET 100 µm 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. Evaluation:…: particularly excellent…: good Δ: somewhat problematic x: poor 1) Thermal releasability Judgment was made based on the peel strength of cellophane tape. The coated surfaces were combined, heat-sealed under the conditions of 150 ° C. × 1 kg / cm ² × 1 second, peeled off from the end, and the releasability was judged. 2) Slipperiness A criterion was used to determine whether the coefficient of friction decreased as compared with a polymer not modified with Silcon. 3) Magic Ink Contamination After drawing a line on the coated surface with Magic Ink ^R , immediately wipe it off with absorbent cotton.
The contamination of the ink before and after was judged. 4) Adhesion Adhesion to PET 100 μm was determined by a grid test.

Claims (1)

Claims: 1. A silicone-modified polymer containing (i) an organopolysiloxane component in its main chain, wherein the amount of silicone modification in the polymer is 3 to the total amount of the polymer.
(Ii) a silicone-modified polymer containing a dimethylpolysiloxane component in a side chain, wherein the amount of the silicone-modified polymer in the polymer is 5 to 70% by weight based on the total amount of the polymer. An image receiving apparatus for receiving an image by a thermal transfer method, characterized in that a certain thermal release polymer is applied as a thermal release agent.
Sheet. 2. The image receiving sheet according to claim 1, wherein the basic skeleton of the polymer of the heat releasing agent is made of polyester . 3. The image receiving sheet according to claim 1, wherein the basic skeleton of the polymer of the heat releasing agent is made of polyurethane . 4. The image receiving sheet according to claim 1, wherein a basic skeleton of the polymer of the heat releasing agent is made of polyamide . 5. The image receiving sheet according to claim 1, wherein the basic skeleton of the polymer of the heat releasing agent comprises a polymer of an ethylenically unsaturated monomer .