JPH061859A - Production of crosslined molding - Google Patents

Abstract

PURPOSE:To obtain a crosslinked molding having excellent shape retention and flexibility and suitable elasticity by firmly bonding an oily gel to the surface of an oil-resistant plastic base through a layer of an undercoating composition of a specified composition. CONSTITUTION:A composition comprising a first rubber component containing double bonds in the molecule (e.g. butadiene rubber) and an oil component capable of dissolving this rubber component (e.g. diethyl sebacate) is poured into a mold of a specified shape or formed into a membrane. Separately, an undercoating composition 2 comprising a synthetic resin component (e.g. acrylic resin) incapable of being dissolved or swollen in the oil component and a second rubber component (e.g. liquid isoprene) containing double bonds in the molecule and being compatible with the synthetic resin component is applied to the surface of an oil-resistant plastic base to form a layer of this composition thereon. A layer 1 of the above composition poured into a mold or formed into a membrane and kept in contact with the layer 2 of the undercoating composition formed on the surface of the base 3 is subjected to crosslinking, gelation and integration to form a crosslinked molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a crosslinked molded article, and more particularly to a crosslinked molded article having an oily gel body adhered to the surface of a substrate.

[0002]

2. Description of the Related Art Conventionally, various types of so-called oily gels have been proposed in which a rubber-like elastic material is mixed with an oily component and subjected to a crosslinking treatment (for example, JP-B-54-2661 and JP-B-54). -4734, Japanese Patent Publication No. 2-6149
No. 6, etc.). Since such oily gels are usually excellent in shape retention, flexibility, elasticity, and cold retention, for example, stress dispersal materials such as mats for pressure sore prevention, sound and vibration damping materials, and head cooling. It is used for belts and cooling macras. Further, in recent years, it has also been used as an ultrasonic transmission medium by utilizing the acoustic characteristics of the oily component contained therein.

As described above, the oily gel body is expected to develop into various products by taking advantage of its characteristics. However, such an oily gel body is not only used by itself, but may be used as a composite form by being adhered to a base material such as plastic or metal from the viewpoint of handleability.

Generally, there are few oily gels having adhesiveness or tackiness, and even if they have adhesiveness, they contain an oily component inside, so that the oily component exudes to the surface thereof It is likely to cause poor adhesion to

Examples of the method for imparting adhesiveness (tackiness) to the oily gel body include a method of reducing the degree of crosslinking during the crosslinking treatment and a method of adding a tackifying resin. However, since such a method changes various properties of the gel body, it cannot be said to be an excellent method.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to improve the poor adhesion of a conventional oily gel body to a base material, and has a high adhesive force to the surface of a plastic base material. It is an object to provide a method for adhering a body to obtain a crosslinked molded body.

[0007]

The inventors of the present invention have made extensive studies to achieve the above-mentioned object, and as a result, in an oily gel body that is difficult to adhere to a plastic substrate, a specific synthetic resin component and rubber component After the undercoating composition consisting of is applied in advance to the surface of the base material to form a layer, a composition for a crosslinked molded article to be an oily gel body is formed on this undercoating composition layer, and each composition is subjected to a crosslinking treatment. It was found that the above object can be achieved by integrally causing gelation, and completed the present invention.

That is, the present invention is for a crosslinked molded article containing a first rubber component which is compatible with an oily component and has at least one double bond in the molecule, and an oily component which dissolves the first rubber component. A step of injecting or forming a film of the composition into a mold of a predetermined shape; a synthetic resin component which does not dissolve or swell in an oily component; and a synthetic resin component which has at least one double bond in its molecule A step of forming a layer of an undercoat composition containing a soluble second rubber component on the surface of an oil-resistant plastic substrate; and a surface of the composition for a crosslinked molded body injected or formed into a mold on the surface of the substrate. A method for producing a crosslinked molded article, comprising the steps of subjecting each composition to a crosslinking treatment in a state where the formed undercoating composition layer is in contact with the composition to cause gelation and integration. .

The composition for a crosslinked molded body used in the production method of the present invention constitutes an oily gel body, and comprises a first rubber component and an oily component which dissolves the rubber component. The first rubber component forms the gel skeleton of an oily gel having high elasticity, high shape retention and flexibility, and is composed of natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile rubber, acrylonitrile. -At least one double bond in the molecule such as butadiene rubber, chloroprene rubber, styrene-chloroprene rubber, isobutylene-isoprene rubber, styrene-isoprene rubber, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, and acrylic rubber. A rubber-like elastic body having is used. Among these elastic materials, synthetic rubber, especially butadiene rubber, isoprene rubber, styrene-
It is preferable to use butadiene rubber. In these rubber-like elastic bodies, the double bond contained in the molecule contributes to the crosslinking reaction described later to cause gelation.

The oily component to be contained together with the first rubber component has a desired gel strength depending on its content,
The elastic modulus can be adjusted. In the production method of the present invention, the oil component is usually 50 to 3000 parts by weight, preferably 300 to 2 parts by weight, based on 100 parts by weight of the first rubber component.
It is preferable to add about 000 parts by weight. Specific examples of the oily substance to be contained include vegetable oils such as olive oil and castor oil, mineral oils such as liquid paraffin and process oil, diethyl sebacate, dioctyl phthalate, dioctyl adipate, ethyl cinnamate, ethyl phenylacetate and olein. Ester oils such as ethyl acidate and benzyl benzoate, animal oils such as squalane and squalene are used.

Among the above oily components, dibasic acid esters such as diethyl sebacate, dibutyl sebacate and dioctyl adipate, and benzene in the molecule such as ethyl cinnamate, ethyl phenylacetate, benzyl benzoate and benzylbutyl phthalate. Has a ring and has a specific gravity of 0.9 at 25 ° C.
Organic compounds of 5 or more are preferable because they have excellent solubility of the first rubber component, low solution viscosity after dissolution, and good workability.

On the other hand, in the production method of the present invention, the undercoat composition formed in layers on the surface of the oil resistant plastic substrate is
It is for improving the adhesive force of the oily gel body to the base material and has an affinity for the base material and the oily gel body. Such an undercoat composition comprises a synthetic resin component which does not dissolve or swell with respect to an oily component contained in the oily gel body, a compound having at least one double bond in the molecule and a phase which is compatible with the synthetic resin component. It contains a second rubber component that melts.

As the synthetic resin component, for example, an acrylic resin, an epoxy resin, a polyamide resin, a polyester resin, a polyurethane resin, a phenol resin or the like can be used alone or in combination of two or more.
These synthetic resin components have the function of increasing the affinity with the base material, and are preferably the same as the plastic base material,
Alternatively, it is preferable to select and use a similar synthetic resin from the viewpoint of improving the adhesiveness. The synthetic resin that is similar to the plastic base material here is one that is skeletally similar to the main component that constitutes the plastic base material (for example, the same bond such as an ester bond, an ether bond, an amide bond, or a urethane bond is a repeating unit. And those having similar solubility parameters (so-called SP values).

The second rubber component contained in the undercoating composition together with the above synthetic resin component causes a crosslinking reaction at the same time when the adjacent crosslinked molded body composition is crosslinked to strengthen both composition layers. It is an important component for adhesion and integration. As such a second rubber component, those exemplified for the first rubber component can be used. Further, since the undercoat composition is applied on the surface of the base material to form a layer having a thickness of about 10 to 200 μm, it is preferable that the coating workability is good. From the viewpoint of such coating workability, it is preferable to use a so-called liquid rubber which has fluidity at the working temperature for the second rubber component, from the viewpoint of solventless coatability. Examples of the liquid rubber that can be used include liquid butadiene rubber, liquid isoprene rubber, and modified liquid rubber that is methacrylated, maleated, or epoxidized. To improve the coating workability, an organic solvent such as toluene, methyl ethyl ketone, ethyl acetate, acetone or xylene may be added to the undercoat composition to adjust the viscosity, if necessary.

The synthetic resin component in the undercoat composition and the second
The content ratio of the second rubber component to the rubber component is 10 to 100 parts by weight, preferably 15 to 40 parts by weight with respect to 100 parts by weight of the synthetic resin component. When the content of the synthetic resin component is high, the adhesiveness with the undercoating composition layer is deteriorated when the composition for crosslinked molded body is crosslinked and gelled. On the other hand, when the content of the second rubber component is high, the composition becomes a base material. Adhesion to the undercoat composition layer may become poor, or a large amount of oily components may migrate into the undercoat composition layer, causing a phenomenon of peeling from the substrate over time.

In the production method of the present invention, the composition for a crosslinked molded article is first poured into a mold having a predetermined shape or formed on a flat surface. On the other hand, the above-mentioned undercoat composition is applied in a layer form on an oil-resistant plastic substrate such as polyester, polystyrene, nylon, polymethylmethacrylate, or polycarbonate to form a film, and the film side (undercoat composition layer side) of this has a predetermined shape. It is brought into contact with the surface of the composition for a crosslinked molded body which is poured into a mold or formed into a film.

In this state, organic peroxide cross-linking or radiation cross-linking is applied to gelate the whole so that each composition layer is integrated. In the case of organic peroxide crosslinking, for example, methyl ethyl ketone peroxide, cyclohexanone peroxide, cumene hydroperoxide, dicumyl peroxide, acetyl peroxide, lauroyl peroxide,
Benzoyl peroxide, t-butylperoxy-2-
Ethyl hexanoate, t-butyl peroxybenzoate, peracetic acid, a low molecular weight copolymer peroxide of a vinyl-based monomer and oxygen, etc. are blended in the composition for cross-linked molding at a temperature below the decomposition temperature. In the cross-linking reaction, the cross-linking reaction is carried out by heating above the decomposition temperature of the organic peroxide. The compounding amount is about 0.05 to 40 parts by weight with respect to 100 parts by weight of the first rubber component. If necessary, a crosslinking reaction accelerator such as cobalt naphthenate or tin octenoate can be added.

On the other hand, in the case of radiation cross-linking, radiation such as γ-rays and electron beams is applied at 0.25 to 5 Mrad, preferably 0.
Irradiate in the range of 5 to 3.0 Mrad. The irradiation dose is 0.
If it is less than 25 Mrad, a crosslinked molded article having sufficient gel strength cannot be obtained, and at an irradiation dose of more than 5 Mrad, the crosslink density becomes large, so that the oily gel body itself becomes too rigid and is contained. The oily component may cause blooming.

A crosslinked molded article can be obtained as described above. However, in the case of a molded article such as a frame body in which the oil-resistant plastic substrate can be used as a grip portion or a holder, the above-mentioned production method is directly applied. A crosslinked molded body can be obtained. On the other hand, when a molded body such as a frame used as a grip or a holder does not have oil resistance, a film-like material is used as the oil-resistant plastic base material, and the base material opposite to the undercoat composition layer forming side is used. The base material can be attached and fixed to the frame body (molded body) by applying an adhesive agent in layers on the surface or by attaching an adhesive tape.

Further, in the present invention, since the rubber component, the synthetic resin component and the oily component are used, heat deterioration, oxidative deterioration, light deterioration and the like are likely to occur at the time of manufacturing or after manufacturing, and various aging preventions are performed for the purpose of preventing these It is preferable to add an agent to the composition for crosslinked molded products and / or the undercoat composition. In addition, various pigments, fragrances, viscosity imparting agents, gel strength enhancers and the like can be added as required.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 480 g of diethyl sebacate was mixed with styrene / butadiene rubber (styrene content 24%, Mooney viscosity [ML1 + 4,
100 ° C.] 32) 120 g was finely chopped and blended, heated to 100 ° C. in a nitrogen gas atmosphere and stirred to completely dissolve, to give a viscous composition for a crosslinked molded article.

Cooling the composition obtained to below 40 ° C.,
Benzoyl peroxide in paste form (BPO content 5
0% by weight, dispersion medium: dioctyl phthalate) 2 g,
After sufficiently stirring, mold this (10 cm × 10
(cm × 2 cm), and degassed.

On the other hand, 50 g of a polyester resin was dissolved in a mixed solvent of toluene / methyl ethyl ketone (50/50% by weight) so that the solid content concentration was 30% by weight, and 10 g of acrylated liquid polybutadiene was added thereto to obtain a uniform solution. An undercoat composition solution was prepared. This was applied on one side of a 25 μm thick polyester film and dried at 40 ° C. for 5 hours to evaporate the solvent to form an undercoating composition layer of 50 μm thick.

Next, the surface of the degassed composition for crosslinked moldings is contact-coated with an undercoating composition layer applied to the surface of a substrate, and heat-treated at 120 ° C. for crosslinked moldings in a mold. The composition was crosslinked and gelled to integrate with the basecoat composition layer. Next, a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides was attached to the opposite surface of the base material to prepare a sheet-like crosslinked molded body shown in FIG.

The produced crosslinked molded article has no stickiness in the oily gel body portion, is flexible and has a high elasticity.
The oily component (diethyl sebacate) in the gel did not transfer to the double-sided pressure-sensitive adhesive tape even when left at 7 ° C. for 7 days, and it was firmly adhered to the polyester film as the base material.
When this sheet-shaped cross-linked molded article was adhered to a frame body made of an aluminum plate and observed for one month in a normal state, good adhesiveness was maintained.

Example 2 500 g of liquid paraffin was mixed with isoprene rubber (cis 1,
4-bond 98%, Mooney viscosity [ML1 + 4, 100 ° C]
90) 60 g was finely chopped and blended, heated to 100 ° C. under a nitrogen gas atmosphere, stirred and completely dissolved to obtain a viscous composition for a crosslinked molded body.

Cooling the composition obtained to below 40 ° C.,
4 g of lauroyl peroxide in paste form (content and dispersion medium are the same as in Example 1) were added and sufficiently stirred, followed by casting in the same mold as in Example 1 and degassing treatment. It was

On the other hand, 50 g of a polyester resin was dissolved in a mixed solvent of toluene / methyl ethyl ketone (50/50% by weight) so that the solid content concentration became 30% by weight, and a methacrylated liquid polyisoprene rubber solution (solvent toluene was added thereto). , Solid concentration 20% by weight) was added to prepare a uniform undercoat composition solution. This was applied on one side of an acrylic resin plate having a thickness of 5 mm and dried at 40 ° C. for 5 hours to volatilize the solvent to form an undercoat composition layer having a thickness of 60 μm.

Next, the surface of the degassed composition for crosslinked moldings is contact-coated with an undercoating composition layer applied to the surface of a substrate, and heat-treated at 100 ° C. for crosslinked moldings in a mold. The composition was crosslinked and gelled to be integrated with the undercoat composition layer to prepare a crosslinked molded body shown in FIG.

The cross-linked molded body thus produced can be used as an ultrasonic coupler for performing image diagnosis using ultrasonic waves,
Since the holder (acrylic resin plate) for fixing the ultrasonic probe (probe) is integrated with the gel, the handling becomes simple. In addition, the gel characteristics of the oily gel body portion were substantially the same as in Example 1, and had excellent gel characteristics and adhesiveness to the substrate.

Example 3 An undercoat composition obtained by filling the composition for a crosslinked molded article obtained in the same manner as in Example 2 into a heat-sealable molding container, performing defoaming treatment, and then coating the polyester substrate surface. Was contacted with the composition for cross-linked molded body.

Cover this with a film for heat sealing,
After performing heat sealing with the molding container, 2.5Mrad
The composition for a crosslinked molded article was cross-linked and gelled by irradiating γ-rays of 1 above to be integrated with the undercoat composition to prepare a crosslinked molded article.

The produced cross-linked molded article had no gel part tackiness, was flexible and had a great elasticity as in Example 2, and peeled from the polyester substrate even after being left at 60 ° C. for 7 days. There was nothing to do, and it adhered firmly.

Comparative Example 1 The composition for a crosslinked molded article obtained in the same manner as in Example 1 was cast into a mold and subjected to defoaming treatment, and then crosslinked with a polyester base material not coated with the undercoat composition. The surface of the body composition was coated and heat-treated at 120 ° C., and the composition for crosslinked molded body in the mold was crosslinked and gelled to prepare a crosslinked molded body.

The produced crosslinked molded article was flexible and rich in elasticity without stickiness in the gel portion as in Example 1, but was not adhered to the polyester substrate and could be easily peeled off. .

Comparative Example 2 Two toluene solutions of acrylated liquid polybutadiene were used.
Apply to one side of 5μm thick polyester film and
It was dried at 0 ° C. for 5 hours to volatilize the solvent to form an undercoat composition layer having a thickness of 30 μm. Then, in the same manner as in Example 1, the surface of the composition for crosslinked molded article that had been degassed was covered with this film and heat-treated at 120 ° C. to crosslink and gel the composition for crosslinked molded article in the mold. Then, a crosslinked molded body was produced.

The produced crosslinked molded article had no tackiness in the gel portion and was flexible and rich in elasticity, and firmly adhered to the undercoat composition, but the adhesiveness between the undercoat composition and the polyester film was high. It was scarce and easily peeled off.

Comparative Example 3 A toluene / methyl ethyl ketone solution of a polyester resin was applied to one side of a 25 μm thick polyester film and dried at 40 ° C. for 5 hours to evaporate the solvent to 30 μm.
A thick undercoat composition layer was formed. Then, in the same manner as in Example 1, the surface of the composition for crosslinked molded article that had been degassed was covered with this film and heat-treated at 120 ° C. to crosslink and gel the composition for crosslinked molded article in the mold. Then, a crosslinked molded body was produced.

The produced crosslinked molded article was not sticky to the gel portion and was flexible and rich in elasticity, but it was not adhered to the undercoat composition and could be easily peeled off.

[0041]

As described above, according to the method for producing a cross-linked molded article of the present invention, excellent shape retention, flexibility and appropriate elasticity
It is possible to bond an oily gel body, in which the contained oily component does not bloom over time, to a substrate with an excellent adhesive force. Therefore, since the composite oily gel body integrated with the base material can be obtained, various applications can be developed in addition to the conventional applications.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sheet-shaped crosslinked molded body obtained in Example 1.

FIG. 2 is a cross-sectional view of a cross-linked molded body as an ultrasonic coupler with a holder, which is obtained in Example 2.

[Explanation of symbols]

 1 Oily Gel 2 Undercoating Composition Layer 3 Oil-Resistant Plastic Base Material 4 Double-sided Adhesive Tape 13 Holder (Acrylic Resin Plate)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C08J 3/28 9268-4F

Claims (4)

[Claims] 1. A composition for a crosslinked molded article, comprising a first rubber component which is compatible with an oily component and has at least one double bond in the molecule, and an oily component which dissolves the first rubber component. A step of injecting into a mold of a predetermined shape or forming a film, a synthetic resin component which does not dissolve or swell in an oily component, and which has at least one double bond in the molecule and is compatible with the synthetic resin component A step of forming a layered composition of an undercoat composition containing the rubber component of 2 on the surface of the oil-resistant plastic substrate, and the surface of the substrate surface of the composition for a crosslinked molded body that was injected or formed into a mold. And a step of subjecting each composition to a cross-linking treatment in a state where the undercoating composition layer is in contact with the composition to cause gelation and integration, and a method for producing a cross-linked molded article. 2. The method for producing a crosslinked molded article according to claim 1, wherein the synthetic resin component that does not dissolve or swell in the oily component is the same or similar synthetic resin as the plastic substrate. 3. The method for producing a crosslinked molded article according to claim 1, wherein the second rubber component is a liquid rubber having fluidity at working temperature. 4. The method for producing a crosslinked molded article according to claim 1, comprising a step of forming an adhesive layer or a pressure-sensitive adhesive layer on the surface of the base material opposite to the surface on which the undercoat composition is formed.