JPS6056191B2 - mixed composition - Google Patents

Description

[Detailed description of the invention] BACKGROUND OF THE INVENTION The present invention relates to mixed compositions.

More specifically, the present invention relates to a mixed composition that imparts releasability.
Silicone has a surface with excellent releasability and gloss, and is used in many applications by effectively utilizing such properties. For example, release paper, which is a type of laminate with a silicone surface layer on a base material, is generally made by sequentially laminating a polyethylene layer and a silicone layer on the surface of glassine paper, parchment paper, kraft paper, clay coated paper, etc. There is. In this case, it is undesirable for the silicone to migrate to other layers in contact with it. The reason is that release paper or release film protects the adhesive layer of adhesive tape, etc., and immediately before use,
-1^jJ-L Tsu ゛ ゛゛-1-4Reno^↓18 ゛゛゛-1-4Reno^↓18 ゛゛゛-1-4ゝゝゝゝゝゝゝゝゝゝ At that time, if the silicone migrates into the adhesive layer, the adhesive force of the adhesive layer will decrease. There is. In order to prevent this, it is necessary to ensure sufficient adhesion between the polyethylene and silicone laminated on the paper. However, the adhesion between polyethylene and silicone cannot be said to be good, so the surface of polyethylene used for these purposes must be treated with corona discharge in advance to impart adhesion to silicone. This is commonly done. However, corona discharge treatment not only makes the process more complicated, but also has problems with the generation of odors and changes over time.

In addition, corona discharge treatment is possible for flat objects such as films and sheets, but cannot be applied to objects with non-planar surfaces such as molded products. Formation of non-migration silicone coatings is generally not practiced. For this reason, polyolefin molded products that effectively utilize the properties of silicone coatings, such as ice trays, molds for ice cream confectionery, and sticky food plates that utilize silicone's releasability, are currently not in use.
The present inventors hereby propose a mixed composition that can be laminated with good adhesion without performing corona discharge treatment or the like when providing a surface layer of releasable silicone on a substrate.

That is, contrary to the prior knowledge that silicones, especially release silicones, are immiscible with other organic polymers,
When a polymer having a polar group is selected as the organic polymer, this polar group-containing polymer is mixed with silicone, and this mixed composition is used as an aqueous emulsion or dispersion for coating, a substantially uniform mixture layer can be formed. was found to be formed on the substrate.

Furthermore, even if the release silicone is mixed in the polar group-containing polymer, the adhesion to the base material is hardly impaired in this mixture layer, and the release silicone is mixed with the polar group-containing polymer. It has the characteristic that the surface removability is hardly impaired even when the surface is coated. Accordingly, the present invention relates to a mixed composition comprising an aqueous emulsion or dispersion containing a polar group-containing polymer and a release silicone; By coating the mixture as a liquid or dispersion onto a substrate, a laminate is formed with a layer of such a mixture on the substrate. In the present invention, as a polymer having a polar group,
Partially neutralized alkali metal salts of ethylene-ethylenically unsaturated carboxylic acid copolymers (ionomer resins), such as sodium salts of ethylene-methacrylic acid copolymers, ethylene-methacrylic acid-isobutyl acrylate terpolymers, etc. Partially neutralized products of alkali metal salts, such as, are used. Such an alkali metal salt partially neutralized product of an ethylene-ethylenically unsaturated carboxylic acid copolymer has an ethylenically unsaturated carboxylic acid content of 2 to 12 mol%, or a degree of neutralization with an alkali metal salt of 30 to 12 mol%. Preferably, 80% is used. Ethylenically unsaturated carboxylic acid content is 2
Mol%. If less than 12 mol % is used, the effect of the presence of polar groups will not be observed and the silicone layer will easily peel off from the substrate. On the other hand, if more than 12 mol % is used, the copolymer will soften and become sticky. This will impede removability. Furthermore, if a neutralization degree of less than 30% is used, the stability of the aqueous emulsion or dispersion will deteriorate, making it impossible to obtain a uniform dispersion, whereas if a degree of neutralization is more than 80%, the substrate This impairs the water resistance of the mixture coating layer formed thereon and impairs its releasability.

These polar group-containing polymers can be used alone, but they can also be used in blends with polyolefins or elastomers that have poor adhesion to silicone. Examples of polyolefins to be blended include polyethylene, polypropylene, polybutene, poly4-methyl-1-pentene, ethylene-vinyl acetate copolymer, and elastomers.
For example, one or more of ethylene-propylene copolymers, ethylene-propylene-diene copolymers, propylene-butene copolymers, polybutadiene, polyisobutylene, etc. can be used. When used as a blend in this way, the desired adhesion effect is achieved when the polar group-containing polymer is mixed in a proportion of about 0.01% or more, preferably about 0.05% or more of the entire blend. Also, good results are obtained when the polar groups in the polymer or blend are about 0.5% or more, preferably 1% or more. The silicone used in combination with these polar group-containing polymers has an organopolysiloxane structure and forms a film through a condensation reaction and an addition reaction.

Examples of the condensation reaction curing type include compositions containing an organopolysiloxane having a hydroxyl group at the end, a silane compound as a curing agent, and an organic acid metal salt as a catalyst added as necessary. Examples of the addition reaction condensation type include compositions containing a siloxane having a vinyl group, a silane compound having a hydroxyl group as a curing agent, and a platinum compound as a catalyst added as necessary. Which reaction-curing silicone composition to select is determined by the properties, curability, film-forming properties, etc. of the silicone. Further, these silicone compositions include one-component type and two-component type, and both can be used in the present invention.

Furthermore, it is classified into room temperature curing type and heat curing type, and both of these types can be used, but those whose curing conditions require heating to a temperature higher than the melting point of the polar group-containing polymer for a long time are This is not preferable because it causes deformation of the mixture layer containing the polar group-containing polymer. Therefore, low temperature curing type materials are generally preferred. A mixed composition of a polymer having a polar group and a silicone can be prepared by mixing the two in advance and then preparing an aqueous emulsion or dispersion, or by mixing the respective aqueous emulsions or dispersions. You can also do it.

In the latter case, by combining the anionicity, cationicity, pH, etc. of each liquid, a mixed liquid can be obtained without agglomeration. The most preferred mixed composition is a mixture of an anionic self-aqueous emulsion of an ionomer resin (Surlini®, a product of Mitsui Polychemical Co., Ltd.) and an aqueous emulsion of an anionic silicone.

When silicone is used in a proportion that is generally in the range of about 2 to 98%, preferably about 10 to 80% of the total weight of the silicone and the polar group-containing polymer, a mixture layer formed from this mixed composition is used. The adhesion to the base material and the releasability from other surfaces with which it comes into contact, such as cellophane tape, are both improved. The substrate on which the mixture layer containing a polar group-containing polymer and silicone is provided includes paper, textiles,
Plastic films, sheets, molded products, metal foils, etc. are used, and the mixed composition can be coated onto these substrates by various known methods.

Coating methods include roll coating, percoat, cast coating, if the coating surface is flat.
Gravure coat, screen coat, knife coat, dip coat, spray coat, brush coat, etc., and for non-planar surfaces, dip coat,
Spray coat, brush coat, etc. are used. After coating, the aqueous medium or solvent is removed by heating and drying. By heating at this time, the curing reaction of the silicone proceeds, and the temperature may be room temperature, but if it is desired to cure quickly, it is desirable to carry out the heating to an extent that does not deform the mixture layer. The curing reaction is approximately 1
The process is completed in about minutes to several hours, and a peelable mixture layer is formed in close contact with the surface of the substrate. After curing, it is possible to further perform secondary molding on the coating, but in general, silicone after curing is stretchable but not thermoplastic, so processing that causes extreme expansion and contraction of a silicone-containing mixture coating is difficult. This is not preferable as it will damage the coating. An example of a laminate in which a mixture layer containing a polymer having a polar group and a releasable silicone is provided on a base material is as follows.
Applications include adhesive tapes and release papers, but it is desirable to make the tape or paper as a base material sufficiently strong and to make the thickness of the mixture layer as thin as possible.

The thickness of the coating film made of this mixture layer is generally approximately 0.1 to 100μ, and the thickness is adjusted by the coating amount and the concentration of each component of the mixture in the coating liquid. . The mixture layer formed from the mixture composition according to the present invention exhibits good adhesion to the substrate even without corona discharge treatment. This becomes possible even for molded products with planar surfaces, making it possible to use the silicone coating laminate in a much wider range of applications than before.

Next, the present invention will be explained with reference to examples.

Example 1 Toray Silicone SM-7272 (wettability improver) 1 ml and Toray Silicone SM-7270 (milky white emulsion containing 30% condensed silicone) in 50 ml of water.
25 ml were added one after another and mixed uniformly.

Next, an aqueous dispersion of a partial sodium salt (degree of neutralization 35%) of ethylene-methacrylic acid (3.5 mol%) copolymer (
Add 25 mt (solid content concentration 30% by weight) and mix with stirring.
In addition, Toray silicone SM-7271 (catalyst) 1m
Added t. The obtained aqueous emulsion formed a homogeneous mixed composition, and no increase in viscosity or gelation was observed. This aqueous emulsion was coated on kraft paper using a brush, heated at 120° C. for 2 minutes, and dried.

The approximately 15μ thick coating formed on the kraft paper base adhered well to the kraft paper, and even when cellophane tape was attached to the coating surface, the cellophane tape could be easily removed. . Example 2 Anionic aqueous dispersion containing 3 weight % of partial sodium salt of ethylene-methacrylic acid (5.4 mol %) copolymer (degree of neutralization 59%) and anion containing μs weight % of silicone Sex emulsion (Toray silicone SH4
9O) were mixed at a volume ratio of 1:1 to form a uniform emulsion mixture composition.

This mixed emulsion was coated on high-quality paper (basis weight 81.4 g/Nt).
) using a roll coater and heated to 150°C.
It was heated and dried with hot air for 1 minute.

Claims (1)

[Scope of Claims] 1. A mixed composition comprising an aqueous emulsion or dispersion containing a partially neutralized alkali metal salt of an ethylene-ethylenically unsaturated carboxylic acid copolymer and a releasable silicone. 2 A copolymer in which the alkali metal salt partially neutralized product of ethylene-ethylenically unsaturated carboxylic acid copolymer has an ethylenically unsaturated carboxylic acid content of 2 to 12 mol% and a degree of neutralization with an alkali metal salt of 30 to 80%. The mixed composition according to claim 1, which is a neutralized product.