JPH09324099A - Unvulcanized rubber composition, rubber molding and production of rubber molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an unvulcanized rubber composition which comprises a diene polymer and an epoxidized EPDM and is excellent in coatability, and to produce a rubber molding from the composition. SOLUTION: This composition comprises a diene polymer, an epoxidized EPDM and a vulcanizing agent. The rubber molding is produced by extruding the composition and then vulcanizing the extruded article. It is desirable that the weight ratio of the diene polymer to the epoxidized EPDM is (80:20) to (30:70) and that the oxirane oxygen content of the epoxidized EPDM is 0.1-2.0wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a diene polymer and an epoxidized ethylene propylene diene terpolymer (hereinafter referred to as “ethylene propylene diene terpolymer”).
It is called DM. ) And an unvulcanized rubber composition having excellent coatability, a rubber molded product comprising the composition, and a method for producing the same.

[0002]

As a technique relating to an unvulcanized rubber composition,
A method for producing a rubber composition such as a weather strip is disclosed in JP-A-3-161329. The technique disclosed in this publication involves forming an adhesive layer made of a nitrile rubber / EPDM compound or the like on the glass portion of a glass run main body made of EPDM. When forming the adhesive layer, an extruder for extruding the glass run main body and an extruder for extruding the adhesive layer are connected to a multicolor extrusion head, and extrusion molding is performed by coextrusion. Next, a urethane coating is applied to the adhesive layer on the glass portion of the glass run body of the extruded product by a general-purpose method, that is, flow coating, brush coating, etc., and then vulcanization is performed.

[0003]

However, in the method disclosed in the above publication, a separate extruder is used for extruding the glass portion of the glass run main body and the adhesive layer, which increases the equipment cost. In addition, since it is necessary to apply urethane paint to the unvulcanized extrudate after extrusion by a general-purpose method, the application means cannot touch the glass run body, and it has a cross-sectional shape that is particularly difficult to develop. In the case of a product, there are parts that are difficult to apply.

On the other hand, Japanese Unexamined Patent Publication (Kokai) No. 5-237448 discloses a technique in which EPDM and polyglycidyl methacrylate are blended in a rubber composition to improve the coating property. It is desired to develop a technique for reducing the amount of polyglycidyl methacrylate and improving the excellent coating property without adding polyglycidyl methacrylate.

[0005]

Means for Solving the Problems As a result of detailed investigation of the effect of addition of epoxidized EPDM, the present inventor has formulated a polyglycidyl methacrylate by blending a diene polymer and epoxidized EPDM. The inventors have found that an unvulcanized rubber composition having excellent coatability can be obtained even when there is no such problem, and that the above problems can be solved, and have completed the present invention.

That is, the present invention provides an unvulcanized rubber composition comprising a diene polymer, epoxidized EPDM and a vulcanizing agent. The blending weight ratio of the diene polymer and the epoxidized EPDM is 80/20 to 30 /.
The above-mentioned unvulcanized rubber composition is 70. In addition, the oxirane oxygen concentration of epoxidized EPDM (same as the oxirane oxygen content) is 0.1.
The above-mentioned unvulcanized rubber composition is provided in an amount of 2.0% by weight. The unvulcanized rubber composition is characterized in that the diene polymer is a block copolymer having a weight ratio of vinyl aromatic hydrocarbon compound / conjugated diene compound of 20/80 to 70/30. To do. Further, the present invention provides a rubber molded product comprising the unvulcanized rubber composition. In addition, the present invention provides a method for producing a rubber molded product, which comprises subjecting the unvulcanized rubber composition to extrusion molding and then vulcanizing the molded product.
Hereinafter, the present invention will be described in detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Monomers which can constitute the diene polymer of the present invention include, for example, vinyl aromatic hydrocarbon compounds, aliphatic diene compounds and alicyclic diene compounds. Styrene as a vinyl aromatic hydrocarbon compound,
Examples thereof include alkylene-substituted styrene such as α-methylstyrene, alkoxy-substituted styrene, vinylnaphthalene, alkyl-substituted vinylnaphthalene, divinylbenzene and vinyltoluene. 1,3 as an aliphatic diene compound
-Butadiene, isoprene, 1,3-pentadiene,
2,3-dimethyl-1,3-butadiene, piperylene,
3-butyl-1,3-octadiene, 2-phenyl-
Examples thereof include 1,3-butadiene. Examples of the alicyclic diene compound include dicyclopentadiene, cyclopentadiene, ethylidene norbornene and the like. The diene polymer of the present invention may be composed of one type or a combination of two or more types selected from these, and may be further copolymerized with ethylene, propylene and the like.

The diene polymer used in the present invention may be a homopolymer, a random copolymer or a block copolymer. When the block copolymer is composed of a vinyl aromatic hydrocarbon compound and a conjugated diene compound, the copolymerization weight composition ratio of vinyl aromatic hydrocarbon compound / conjugated diene compound is 20/80 to 70/30. Is preferred, and particularly preferred is 30/70 to 60/40.
This is because an unvulcanized rubber composition having excellent coatability can be obtained in this range.

The epoxidized EPDM used in the present invention is epoxidized EPDM. EPDM that can be used has a number average molecular weight of 2,000 to 40,
It is preferably 000, particularly preferably 3,000 to 25,000. Also, the iodine value of EPDM is 5
It is preferably -50, particularly preferably 10-35. If it is EPDM of this range, what is marketed can be used. In addition, as a typical example of the diene compound which comprises EPDM, dicyclopentadiene, cyclopentadiene, ethylidene norbornene etc. which have an alicyclic skeleton can be illustrated. Other diene compounds include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, phenyl-1, Aliphatic diene compounds such as 3-butadiene may be mentioned. In the present invention, EPDM prepared by combining one or more diene compounds among these may be used.

The epoxidized EPDM can be obtained by a method of adding an epoxidizing agent to EPDM and heating, or a method of adding a compound capable of becoming an epoxidizing agent in the epoxidation reaction system to EPDM and then heating. Examples of the epoxidizing agent include organic peracids such as formic acid, peracetic acid, perpropionic acid, and perbenzoic acid, and organic hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide. These peroxides are preferably anhydrous, but they can be epoxidized by using hydrogen peroxide. Further, as a solvent for percarboxylic acids, hydrocarbons such as hexane, organic acid esters such as ethyl acetate, and aromatic hydrocarbons such as toluene can be used. As a compound that can serve as an epoxidizing agent in the reaction system, there is a combination of carboxylic acid such as formic acid, acetic acid, and propionic acid and hydrogen peroxide. In this case, the epoxidation reaction is preferably carried out in the presence of a solvent inert to the epoxidizing agent and the like. In a system using hydrogen peroxide, hydrogen peroxide and a lower carboxylic acid such as formic acid or acetic acid are reacted in advance to produce a percarboxylic acid, and this carboxylic acid is added to the reaction system as an epoxidizing agent, and the presence of a solvent is present. The epoxidation reaction is carried out in the presence or absence of oxidization. Alternatively, hydrogen peroxide may be used for epoxidation in the presence of a catalyst such as an osmium salt and tungstic acid, and a solvent.

An organic solvent can be used for the epoxidation. Examples of the organic solvent that can be used include linear or branched hydrocarbons such as hexane and octane, and alkyl-substituted derivatives thereof. Further, alicyclic hydrocarbons such as cyclohexane and cycloheptane or their alkyl-substituted derivatives can be exemplified. further,
Benzene, naphthalene, toluene, xylene and other aromatic hydrocarbons or alkyl-substituted aromatic hydrocarbons, methyl acetate, ethyl acetate and other aliphatic carboxylic acid esters,
Examples thereof include halogenated hydrocarbons such as chloroform. Among these, cyclohexane, ethyl acetate, chloroform, toluene, xylene, from the solubility of the epoxidized product and the ease of subsequent recovery of the organic solvent,
It is desirable to use hexane. The amount of solvent used is E
100 to 400 parts by weight of PDM, preferably 100 to 400
Parts by weight, particularly preferably 150 to 300 parts by weight.

The reaction temperature for epoxidation is from 20 ° C to 80 ° C.
C. is suitable, particularly 30 to 60.degree. C. is preferred. If the reaction temperature is lower than 20 ° C, the reaction rate is too slow to be practical. On the other hand, if the temperature is higher than 80 ° C, the self-decomposition of the peroxide becomes remarkable, which is not preferable. The reaction may be carried out under slightly reduced pressure or increased pressure as long as the solvent composition and the reaction temperature do not change.

The reaction molar ratio (double bond amount / peroxide pure content) of the double bond content and the peroxide pure content in the epoxidized product is
The range of 1.0 to 2.0 is suitable, and the range of 1.1 to 1.8 is particularly preferable.

The reaction time for epoxidation is usually 1 to 5 hours, though it varies depending on the reaction temperature. When it is less than 1 hour, the conversion rate of the double bond is low and not practical. On the other hand, if it is 5 hours or more, for example, when peracetic acid is used as the peroxide, the addition reaction between the epoxidized product and acetic acid increases, which causes a decrease in yield, which is not preferable.

The oxirane oxygen concentration of the epoxidized EPDM used in the present invention can be adjusted by appropriately changing the reaction ratio of the epoxidizing agent. The oxirane oxygen concentration of the epoxidized EPDM used in the present invention is 0.1-0.1%.
It is preferably in the range of 2.0% by weight, and particularly preferably 0.
It is in the range of 12 to 1.8% by weight. This is because the paintability is particularly excellent in this range.

A vulcanizing agent is added to the unvulcanized rubber composition of the present invention. As the vulcanizing agent, sulfur, other metal oxides such as zinc oxide, and organic peroxides can be used. Examples of the organic peroxide include benzoylperoxide, lauroylperoxide, bis (t-butylperoxy) -3,
An example is 3,5-trimethylcyclohexane. The compounding amount of the vulcanizing agent is 0.2 to when the total amount of the diene polymer and the epoxidized EPDM is 100 parts by weight.
It is preferably in the range of 2.5 parts by weight, and in particular,
It is in the range of 0.5 to 2.0 parts by weight. When sulfur is used as the vulcanizing agent, it is preferable to use 20 to 150% by weight of the vulcanization accelerator with respect to the vulcanizing agent. Examples of the vulcanization accelerator include stearic acid, oleic acid, lauric acid, fatty acids such as zinc stearate and derivatives thereof, diphenylguanidine, 2-mercaptobenzothiazole, and organic compounds such as tetramethylthiuram monosulfide. it can. Further, it is also possible to use an inorganic compound such as zinc white, zinc carbonate and magnesium oxide. In the present invention, these may be used alone or in combination of two or more.

The rubber composition of the present invention contains, as a filler, plastic fiber, glass fiber, wollastonite, diatomaceous earth, wood powder, natural calcium silicate, asbestos powder, talc,
Calcium carbonate, kaolin, celite and the like can be used. When the total amount of the diene polymer and the epoxidized EPDM is 100 parts by weight, the amount of these fillers blended is
It is preferably in the range of 1 to 60 parts by weight, and in particular,
It is in the range of 5 to 40 parts by weight. In the present invention, these fillers may be used alone or in combination of two or more.

The unvulcanized rubber composition of the present invention can be molded by extrusion molding, compression molding or the like. Particularly preferred is extrusion molding. Further, the extruded product can be vulcanized, that is, heat-treated to cause cross-linking in the unvulcanized rubber composition to produce a rubber molded product. In addition,
When applying a coating to the unvulcanized rubber composition of the present invention,
The coating may be applied and cured after vulcanization, but it is also possible to apply the coating before vulcanization and simultaneously perform vulcanization and curing of the coating.

As the paint that can be used for the unvulcanized rubber composition of the present invention, urethane paint, acrylic paint, polyester paint can be used. Of these, urethane-based paints are preferable. In particular, the solventless urethane coating composition is preferably composed of a polyol component having an OH group at the terminal and an isocyanate component 2 liquid. In addition, 1 in which the block type isocyanate was blended with the polyol component
It may be a liquid type paint. The paint is preferably completely solvent-free. When a solvent is added, a solvent having a boiling point of 150 ° C. or higher can be added at a ratio of less than 20% by weight. With this ratio, the coating film does not foam due to the heat of the vulcanized layer, and therefore the appearance does not deteriorate and the abrasion durability does not deteriorate.

[0020]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. All "parts" and "%" are based on weight.

(Measurement Items) (1) Adhesion Force The adhesion force was measured by measuring each vulcanized sample with a width of 5 mm × 10.
Cut into 2 pieces of 0mm length x 1.5mm thickness, glue the urethane smooth surfaces to each other with an adhesive (instant adhesive "Zerotime" made by Cemedine Co., Ltd.), and use the Tensilon tensile tester made by Shimadzu Was measured. (2) Peeling state The peeling state was visually observed. After the peeling, the case where only the coating film was attached to the test piece was defined as the interfacial peeling, and the case where the base material was adhered was defined as the base material peeling.

(Synthesis Example) An ethylene propylene diene terpolymer (EPDM) having an iodine value of 20 and a number average molecular weight of 5,300 was placed in a four-necked round bottom flask having an internal volume of 1,000 ml equipped with a thermometer, a stirrer and a reflux condenser. 100
g and 200 g of toluene as a solvent were mixed. This was heated to 50 ° C., and 30.0 g of a 30% pure peracetic acid-ethyl acetate solution was added dropwise using a dropping funnel to react.
After completion of the reaction, the product was washed with water to remove acetic acid derived from peracetic acid, and then the solvent was removed under reduced pressure to obtain 89.0 g of epoxidized EPDM having an oxirane oxygen concentration of 0.9%.

(Preparation of Urethane Paint) According to the blending ratio shown in Table 1, a solventless urethane paint is prepared by adding a liquid to a urethane resin component obtained from two liquids of a polyol component having an OH group at the molecular end and an isocyanate component. Dimethyl silicone oil was added as a lubricant, and fluorine resin powder (particle size 20 to 100 μm), molybdenum disulfide, nylon (average particle size 50 μm), and polyethylene (average particle size 50 μm) particles were added as a solid lubricant.

[0024]

[Table 1]

(Examples 1 to 4 and Comparative Example) Using the epoxidized EPDM obtained in the synthesis example, an unvulcanized rubber composition was produced with the composition shown in Table 2. Next, the obtained unvulcanized rubber composition was extruded and then vulcanized, and then the above urethane-based paint was applied. The adhesive force and the peeled state were observed and shown in Table 2.

[0026]

[Table 2]

The adhesion of the comparative example was 0.3 kg / cm or less, and the urethane slipping layer coated with the urethane coating caused interfacial peeling. Although not shown in the examples, when 80 parts by weight or more of epoxidized EPDM was added, it reacted with the vulcanization accelerator, the vulcanization was delayed, and the tear strength was reduced by about 10%.

[0028]

According to the present invention, there is provided an unvulcanized rubber composition comprising a diene polymer and epoxidized EPDM, a rubber molded product comprising the composition, and a method for producing the same. Since the unvulcanized rubber composition of the present invention has excellent coatability, it is possible to easily produce a rubber molded product having a complicated shape.

Claims (6)

[Claims] 1. An unvulcanized rubber composition comprising a diene polymer, epoxidized EPDM and a vulcanizing agent. 2. The unvulcanized rubber composition according to claim 1, wherein the compounding weight ratio of the diene polymer and the epoxidized EPDM is 80/20 to 30/70. 3. The unvulcanized rubber composition according to claim 1 or 2, wherein the oxirane oxygen concentration of the epoxidized EPDM is 0.1 to 2.0% by weight. 4. The diene polymer has a weight ratio of vinyl aromatic hydrocarbon compound / conjugated diene compound of 20/80 to 7.
The unvulcanized rubber composition according to any one of claims 1 to 3, which is a 0/30 block copolymer. 5. A rubber molded product made of the unvulcanized rubber composition according to claim 1. 6. A method for producing a rubber molded product, which comprises extruding the unvulcanized rubber composition according to claim 1 and then vulcanizing the molded product.