JPH0688381B2 - Vulcanized rubber sheet for surface processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is suitable for surface treatment such as forming an adhesive layer on the surface of a vulcanized rubber sheet or coating with a rubber coating. Vulcanized rubber sheet for automobiles.

(Prior Art) Conventionally, vulcanized rubber sheets have been subjected to various surface treatments according to their final use.

For example, when a rubber sheet is punched out and used as various rubber packings, an adhesive tape is attached to the surface of the rubber sheet in advance to provide an adhesive layer, or various kinds of spray painting, gravure printing, screen printing, etc. are applied to the surface of the rubber sheet. Surface treatment such as painting.

By the way, when the above-mentioned surface treatment is directly applied to a vulcanized rubber sheet that has not been subjected to any treatment, chemicals such as a vulcanizing agent, an antioxidant and a plasticizer contained in the rubber sheet are exuded on the surface. Peeling of the adhesive layer or coating occurs, and it is difficult to do this without problems. Therefore, the following treatments are usually performed as a pretreatment for surface treatment.

That is, a buff is used to polish the surface of a rubber sheet using a buff, a chemical treatment such as sulfuric acid is used to modify the surface, and unvulcanized rubber is dusted and then vulcanized to form a powder layer on the surface. A powdering process was performed.

(Problems to be Solved by the Invention) However, the above-described buffing requires labor and skill for the work, raises the cost, and is not very suitable as a pretreatment for coating.

Further, the chemical treatment involves a risk in the work and the cost is also very high, and the dusting treatment is a troublesome work and its effect is not sufficient and the adhesive layer is easily peeled off. There was a point.

An object of the present invention is to solve these problems, and an object thereof is to provide a vulcanized rubber sheet for surface processing, which can easily carry out pretreatment for surface processing at low cost, and has a remarkable effect. To do.

(Means for Solving the Problems) The present invention is a polyfunctional compound having at least two polymerizable unsaturated groups selected from an allyl group, a methacryloyl group and an acryloyl group on its surface in one molecule. The above-mentioned problems are solved by a vulcanized rubber sheet for surface processing in which a coating layer of a polyfunctional monomer is integrally formed on the surface by heating and pressing an unvulcanized rubber sheet coated with a monomer.

The details of the present invention will be described below.

Examples of the rubber of the rubber sheet in the present invention include various rubbers such as natural rubber (NR), IR, SBR, BR, NBR, CR, IIR, EP.
Known rubbers such as M and EPDM are exemplified, and these are used alone or in combination of two or more.

A vulcanizing agent, a vulcanization accelerator, an activator, an antiaging agent, a reinforcing agent, a bulking agent, a softening agent, and their commonly used compounding agents are added to these rubbers.

The compounding amount of the compounding agent can be appropriately selected according to the properties of the rubber sheet.

The polyfunctional monomer applied to the surface of the unvulcanized rubber sheet may be any one as long as it has at least two polymerizable unsaturated groups such as allyl group, acryloyl group and methacryloyl group in one molecule. May be.

Among such polyfunctional monomers, examples of the polyfunctional monomer having an allyl group include triallyl cyanurate and triallyl isocyanurate. Examples of polyfunctional monomers having an acryloyl group include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, butanediol diacrylate, hexanediol. Diacrylate, neopentyl glycol diacrylate, phenylene diacrylate, glycerin diacrylate, glycerin triacrylate, diglycerin tetraacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, N, N'-methylenebis acrylic Other than epoxy resin, polyester oligomer having hydroxy group or carboxy group,
Examples thereof include epoxy acrylates, polyester acrylates, urethane acrylates, and melamine acrylates obtained by reacting urethane oligomers having an isocyanate group, melamines having a methylol group or an alkoxy group with acrylic acid, hydroxyethyl acrylate, and the like. Further, examples of the polyfunctional monomer having a methacryloyl group include monomers corresponding to the above polyfunctional monomers having an acryloyl group. At least one polyfunctional monomer having a polymerizable unsaturated group is used.

Among the polyfunctional monomers having a polymerizable unsaturated group, a polyfunctional monomer having three or more polymerizable unsaturated groups in one molecule, particularly an acryloyl group or a methacryloyl group, especially trimethylolpropane triacrylate and trimethylol Propane trimethacrylate is preferred.

Note that other monofunctional monomers such as methyl acrylate and butyl methacrylate may be used together.

The rubber sheet according to the present invention is manufactured as follows using the polyfunctional monomer.

First, an unvulcanized rubber is appropriately kneaded with the above-mentioned compounding agent to form an unvulcanized rubber sheet, and a polyfunctional monomer is applied to the surface of the unvulcanized rubber sheet, which is then heated and pressurized so as not to be applied. At the same time when the vulcanized rubber sheet is vulcanized, a coating layer formed by polymerizing a polyfunctional monomer is formed on the surface by fusion bonding.

When the polyfunctional monomer is applied to the surface of the unvulcanized rubber sheet, its application amount can be appropriately set within a range that does not adversely affect the subsequent surface processing, and usually an amount that can be uniformly applied, for example, 50 g / m 2. ^{A value of 2} or less is sufficient.

The vulcanization of the unvulcanized rubber sheet is, for example, 100 to 200.
It can be carried out under the conditions of heating at about ℃ and pressurizing at about 1 to 50 kg / cm ² . By this heating and pressurization, the polyfunctional monomer is polymerized, and at that time, it is fused and integrated with the rubber sheet to form a uniform coating layer.

(Function) The vulcanized rubber sheet thus obtained has a very good integrity with the adhesive layer and the coating material for rubber due to the coating layer formed on the surface, and the adhesive layer, etc. can be easily removed from the rubber surface. Does not peel off.

INDUSTRIAL APPLICABILITY The rubber sheet according to the present invention can be produced easily and with high productivity, and is suitable for applying various surface treatments as a surface treatment sheet which is inexpensive and has excellent characteristics.

(Example) An unvulcanized rubber composition comprising the following components (1) to (7) was prepared and formed into a thickness of 1.0 mm to prepare an unvulcanized rubber sheet.

(1) SBR (Asahi Kasei Corp., trade name SBR Sorprene 12
04) 100 parts by weight (2) Carbon black as a reinforcing agent (Asahi Carbon Co., Ltd., trade name Asahi 35 (SRF)) 100 parts by weight (3) Process oil 30 parts by weight as a softening agent (4) Vulcanization Zinc Hua No. 1 as an auxiliary agent (New Year Chemical Co., Ltd.)
5 parts by weight (5) Processing aid, stearic acid as a dispersant (manufactured by NOF CORPORATION) 1 part by weight (6) Polyfunctional monomer as a co-vulcanizing agent (manufactured by Seiko Chemical Co., Ltd., Product name Highcross M) 3.5 parts by weight (7) Organic peroxide as a vulcanizing agent (NOF Corporation)
Product name: PERPEXA 3M-40) 5 parts by weight 10 to 20 g of trimethylolpropane trimethacrylate (manufactured by Seiko Kagaku Co., Ltd., trade name Hicross M), which is a multifunctional monomer, on the surface of this unvulcanized rubber sheet. Apply m ² and
This is heated and pressed at a temperature of 170 ° C and a pressure of 5 kg / cm ² to vulcanize the unvulcanized rubber sheet and at the same time, a coating layer of a 10-micron-thick polyfunctional monomer is integrally formed on its surface. A vulcanized rubber sheet was obtained.

The adhesive force with the adhesive layer in the rubber sheet of the above example is JI
When tested under the following conditions according to S K6301, the results shown in Table 1 were obtained.

Testing machine: Shimadzu Autograph AG-500C (Shimadzu Corporation)
Sample): Sheet with a width of 25.0 ± 0.5 mm and a length of 100 mm or less with adhesive tape (Nitto Denko Co., Ltd., Knit No. 501) attached to the surface of the rubber sheet. Tension speed: 200 mm / min. As a test, the same test as above was performed on a rubber sheet that was not treated at all (Comparative Example (1)) and a rubber sheet that was dusted (Comparative Example (2)).

As is clear from Table 1, the rubber sheets of Examples had a significantly large adhesive force with the adhesive tape, the rubber sheet and the adhesive tape were not peeled off, and cohesive failure was observed on the adhesive tape. It was

(Effects of the Invention) As described above, according to the vulcanized rubber sheet for surface processing of the present invention, since the rubber sheet holds the coating layer of the polyfunctional monomer on the surface thereof, the adhesive force with the adhesive layer and the coating material. Excellent in integration with.

Moreover, it is sufficient to simply apply the polyfunctional monomer to the unvulcanized rubber and then vulcanize it, without requiring complicated work or steps,
A rubber sheet suitable for various surface treatments can be efficiently obtained at low cost.

Claims (1)

[Claims] 1. An unvulcanized rubber having a surface coated with a polyfunctional monomer having at least two or more polymerizable unsaturated groups selected from an allyl group, a methacryloyl group and an acryloyl group in one molecule. A vulcanized rubber sheet for surface processing, in which a coating layer of a polyfunctional monomer is integrally formed on the surface by heating and pressing the sheet.