JPH0611821B2 - Rubber composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rubber-like polymer (hereinafter sometimes abbreviated as EP rubber) composed of ethylene and α-olefin and / or non-conjugated diene containing a phenolic hydroxyl group. The present invention relates to a rubber composition having improved roll adhesion and tackiness in an unvulcanized state without degrading the vulcanization rate and physical properties of the EP rubber in a vulcanized state by compounding the cyclopentadiene resin.

Conventional technology and problems to be solved by the invention EP rubber has excellent ozone resistance, weather resistance, heat resistance, etc., and is widely used in automobile parts, building materials, and various industrial rubber products. However, there is a drawback in that the roll wrapping property and the tackiness in the unvulcanized state are inferior, which causes troubles during the processing of the product.

The roll wrapping property here means EP using a roll mill.
It is the wrapping property around a roll mill at the time of mixing a system rubber and various rubber compounding agents, and if this is insufficient, it takes a lot of labor and time to mix the rubber compounding agents.

Adhesiveness is the property of joining rubber when contacting rubber or rubber and other substances under appropriate pressure.For example, in a tire or a tube, rubber is joined to form a shape, Vulcanization is performed in this state to obtain a product, but if the adhesive strength of the unvulcanized rubber is insufficient, it will be difficult to vulcanize while maintaining the required shape, and also the adhesive force on the contact surface after vulcanization There is a problem that it is lowered and peeling is easy.

Various tackifiers and processing aids have been proposed so far in order to compensate for the above-mentioned drawbacks, but none of them have satisfactory performance. For example, in the known tackifying resins coumarone resin, terpene resin, and aliphatic petroleum resin, almost no improvement in tackiness is observed, and when a developing oil is used, if a large amount is used, the tackiness is improved to some extent. However, there is a drawback that the physical properties of the rubber composition after vulcanization are deteriorated. Furthermore, other Japanese Patent Publication No. 46-21897 and Japanese Unexamined Patent Publication No. 51-
No. 87555 and the like disclose some tackifiers, but none of them are sufficient to solve the above-mentioned drawbacks.

The object of the present invention is to provide an EP with improved roll adhesion and tackiness.
A rubber composition is provided.

Means for Solving the Problems As a result of intensive investigations by the inventors to solve the above problems, the above problems can be solved by incorporating a cyclopentadiene resin containing a phenolic hydroxyl group into an EP rubber. It was confirmed that the present invention was achieved.

That is, the present invention is based on 100 parts by weight of EP rubber, (In the formula, H represents hydrogen, R represents an alkyl group having 1 to 3 carbon atoms, m and n are 0 or an integer of 1 or more, and m + n =
A 5-membered ring compound having a conjugated double bond represented by
Or its Diels-Alder adduct (component A) 10
0 parts by weight and at least one component (component B) selected from monohydric and polyhydric phenols and their alkyl-substituted compounds 2 to 2
0.5 to 0.5 parts by weight of a phenolic hydroxyl group-containing cyclopentadiene resin obtained by copolymerization with 200 parts by weight of
The present invention relates to a rubber composition containing 30 parts by weight.

The EP rubber used in the present invention is produced by copolymerizing ethylene, α-olefin and / or non-conjugated diene using a known catalyst such as a Ziegler-Natta catalyst. Examples of the α-olefin used as the copolymerization monomer include propylene, 1-butene, and 1-pentene, which are α-olefins having 3 to 5 carbon atoms. Of these, propylene is particularly preferable.

Examples of the non-conjugated dienes used as the copolymerization monomer include the following compounds, and at least one of them is used.

Dicyclopentadiene, tricyclopentadiene, 5-
Methyl-2,5-norbornadiene, 5-methylene-2
-Norbornene, 5-ethylidene-2-norbornene,
5-isopropylidene-2-norbornene, 5-isopropenyl-2-norbornene, 5- (1-butenyl)-
2-norbornene, cyclooctadiene, vinylcyclohexene, 1,5,9-cyclododecatriene, 6-methyl-4,7,8,9-tetrahydroindene, 2,
2'-dicyclopentenyl trans-1,2-divinylcyclobutane, 1,4-hexadiene, 2-methyl-
1,4-hexadiene, 1,6-octadiene, 1,7
-Octadiene, 1,8-nonadiene, 1,9-decadiene, 3,6-dimethyl-1,7-octadiene, 4,
Examples thereof include 5-dimethyl-1,7-octadiene, 1,4,7-octatriene, and 5-methyl-1,8-nonadiene.

Of these non-conjugated dienes, 5-ethylidene-2-norbornene and / or dicyclopentadiene are preferred.

The EP rubber used in the present invention has a composition ratio of 48 to 80 mol% ethylene, 50 to 20 mol% α-olefin and 0 to 10 mol% non-conjugated diene. In the present invention, among these EP rubbers, the Mooney viscosity [ML
_{When 1 + 4} (100 ° C.)] is 20 or more, particularly 50 or more, a more excellent effect is exhibited.

In the present invention, the cyclopentadiene resin containing a phenolic hydroxyl group, which is blended with the EP rubber, has the general formula (In the formula, H represents hydrogen, R represents an alkyl group having 1 to 3 carbon atoms, m and n are 0 or an integer of 1 or more, and m + n =
5) and / or its Diels-Alder adduct (component A) 1 having a conjugated double bond represented by
Obtained by copolymerizing with 100 parts by weight of 2 to 200 parts by weight, preferably 5 to 150 parts by weight of at least one kind (component B) selected from monohydric and polyhydric phenols and their alkyl-substituted compounds. To be The copolymerization of (Component A) and (Component B) is carried out at a reaction temperature of 150 to 300 ° C., preferably 200 to 280 ° C., and a reaction time of 10 minutes to 20 hours, preferably 1 hour to 10 hours. You can

When carrying out the copolymerization reaction of (Component A) and (Component B), aromatic hydrocarbons such as benzene, toluene and xylene are used as a solvent in an amount of 5 per 100 parts by weight of (Component A) + (Component B).
It is also possible to carry out by containing up to 200 parts by weight. After the polymerization reaction, the solvent is removed from the reaction product by a conventional method such as distillation, but the unreacted monomer and low polymer may be removed if necessary.

In the production of the cyclopentadiene resin containing a phenolic hydroxyl group used in the present invention, if the amount of (Component B) is less than 2 parts by weight relative to 100 parts by weight of (Component A), the roll winding property is insufficient. On the other hand, if it exceeds 200 parts by weight, the vulcanization rate is delayed and the physical properties in the vulcanized state are deteriorated.

As the above-mentioned (Component A), cyclopentadiene, methylcyclopentadiene and the like, and as Diels-Alder adducts thereof, dicyclopentadiene,
Cyclopentadiene-methylcyclopentadiene co-duplex, tricyclopentadiene, and the like, and mixtures thereof are industrially preferably used, and among these, cyclopentadiene, dicyclopentadiene, or a mixture of both is particularly preferable.

It is not always necessary that cyclopentadiene, dicyclopentadiene or an alkyl-substituted derivative thereof have good purity, but it is preferable that 80% by weight or more of cyclopentadiene, dicyclopentadiene or an alkyl-substituted derivative thereof is present. In addition, dicyclopentadiene, dimethylcyclopentadiene, cyclopentadiene-methylcyclopentadiene co-diene can be obtained by thermal dimerization of cyclopentadiene and methylcyclopentadiene contained in the C ₅ fraction of high temperature pyrolysis by-product oil such as naphtha. A condensed fraction obtained by removing C ₅ components such as C ₅ olefin and C ₅ paraffin and other by-products by distillation after forming a mixture of monomers and the like may be used. (Component B) is at least one selected from monohydric and polyhydric phenols and their alkyl-substituted compounds. The alkyl-substituted product is preferably one in which 1 to 3 alkyl groups having 1 to 12 carbon atoms are substituted. Specific examples thereof include monohydric phenols such as phenol, cresol, ethylphenol, propylphenol, butylphenol, tert-butylphenol, aluminum phenol, hexylphenol, octylphenol, nonylphenol and dodecylphenol, and polyhydric compounds such as hydroquinone, resorcin, catechol and bisphenol. Examples include phenol. (Component B) not only improves the roll winding property, but also has the effect of further improving the adhesive strength.

Further, in the production of the above-mentioned phenolic hydroxyl group-containing cyclopentadiene resin, it is also possible to use an unsaturated component in the petroleum fraction, particularly an unsaturated aromatic component, in an amount equal to or less than the (component A). is there. For example, styrene, α-methylstyrene, vinyltoluene, indene, methylindene, and a mixture thereof can be used, and a so-called C ₉ fraction that is by-produced during decomposition of naphtha or the like is industrially preferable.

Further, the resin may be hydrogenated and used for the purpose of improving the hue or odor.

The cyclopentadiene resin containing a phenolic hydroxyl group used in the present invention has a ring and ball method (JIS K-2531-60).
It is preferable that the softening point is 50 to 180 ° C., especially 60 to 160 ° C. When the softening point is lower than 50 ° C., not only the physical properties such as modulus of the rubber composition after vulcanization remarkably decrease, but also the resin causes blocking and the scouring workability deteriorates. On the other hand, 180 ° C
If it is higher, it becomes difficult to uniformly disperse it in the rubber.

The amount of the phenolic hydroxyl group-containing cyclopentadiene resin used in the present invention is EP rubber 10
0.5 to 30 parts by weight, preferably 2 to 0 parts by weight
20 parts by weight. If the compounding amount is less than 0.5 part by weight, the effect of the addition is not obtained, and the roll winding property and the tackiness are not improved. On the other hand, when the amount is more than 30 parts by weight, the vulcanization rate is delayed and the modulus of the rubber composition after vulcanization is remarkably lowered.

In the present invention, in addition to the phenolic hydroxyl group-containing cyclopentadiene resin, compounding agents usually used in the rubber industry, for example, reinforcing filler, vulcanizing agent, vulcanization accelerator, vulcanization accelerating aid, softening agent , An anti-aging agent and the like can be appropriately compounded in the amounts usually used.

Further, known tackifying resins, for example, chroman resin, terpene resin, phenol resin, etc., in the range of equal to or less than the equivalent amount of the phenolic hydroxyl group-containing cyclopentadiene resin defined in the present invention, and the phenolic hydroxyl group-containing cyclone defined in the present invention. The pentadiene resin and the known tackifying resin can be used together in a range of 30 parts by weight or less based on 100 parts by weight of the EP rubber.

Further, in the present invention, various rubbery polymers such as natural rubber, styrene-butadiene rubber, butyl rubber, chlorinated butyl rubber, brominated butyl rubber, and butadiene-acrylonitrile rubber may be blended as necessary, but the blending amount is EP. The amount of the system rubber is preferably equal to or less than that of the system rubber, and if too much of the above rubber polymer is used, the weather resistance and heat resistance, which are the features of the EP rubber, may be impaired, which is not preferable.

The rubber composition of the present invention is obtained by mixing the EP rubber, the phenolic hydroxyl group-containing cyclopentadiene resin specified in the present invention, the compounding agent and the like with a mechanical mixer such as a roll mill or a Banbury mixer.

Examples Hereinafter, Examples will be shown in order to specifically clarify the content of the present invention, but these are only a few of them, and the present invention is not limited to the Examples unless it goes against the gist thereof. Absent.

Synthesis Example 1 409 g of dicyclopentadiene having a purity of 96%, 291 g of phenol and 300 g of mixed xylene were heated and reacted at 260 ° C. for 6 hours while stirring in an autoclave. After completion of the reaction, the autoclave was cooled, and then the content was distilled to remove unreacted monomers, low polymer and xylene, and 521 g of Resin I was obtained as a bottom residue. Resin I had a softening point of 104.5 ° C and a hydroxyl value of 137 (mgKOH / g) Synthesis Example 2 495 g of dicyclopentadiene having a purity of 96% and 541 g of mixed cresol were heated and reacted at 265 ° C for 6 hours in an autoclave. Was treated in the same manner as in Synthesis Example 1 to obtain 722 g of Resin II. Resin II had a softening point of 91 ° C. and a hydroxyl value of 151 (mgKOH / g).

Synthesis Example 3 503 g of 96% pure dicyclopentadiene, 197 g of mixed cresol and 300 g of mixed xylene were heated and reacted in an autoclave at 265 ° C. for 2 hours, and treated in the same manner as in Synthesis Example 1 to obtain 509 g of Resin III. Resin III
Has a softening point of 105.5 ° C and a hydroxyl value of 81.5 (mgKO
H / g).

Synthesis Example 4 C ₅ decomposition fraction (boiling point 28 to 6) produced as a by-product when ethylene and propylene are produced by steam cracking of naphtha
(0 ° C.) at 120 ° C. for 4 hours to remove C ₅ fraction by distillation, 85% dicyclopentadiene and 10%
A residue containing cyclopentadiene was obtained. 332 g of the residue containing 85% of dicyclopentadiene, 378 g of mixed cresol and 300 g of mixed xylene were heated and reacted in an autoclave at 280 ° C. for 8 hours, and treated in the same manner as in Synthesis Example 1 to obtain 480 g of Resin IV. . This resin IV has a softening point of 91 ° C and a hydroxyl value of 151 (mgKOH
/ G).

Synthesis Example 5 439 g of dicyclopentadiene having a purity of 96%, 124 g of an aromatic fraction having a boiling range of 140 to 280 ° C. produced by thermal decomposition of naphtha, 199 g of phenol, and 238 g of mixed xylene were heated at 265 ° C. for 8 hours in an autoclave. React and treat as in Synthesis Example 1 to obtain 597 g of Resin V
was gotten. Resin V has a softening point of 98.5 ° C. and a hydroxyl value of 92. (MgKOH / g).

Comparative Synthesis Example 500 g of dicyclopentadiene having a purity of 96% and 500 g of mixed xylene were charged into an autoclave, heated and reacted at 260 ° C. for 2 hours, and treated in the same manner as in Synthesis Example 36.
3 g of resin VI was obtained. The softening point of Resin VI was 93 ° C.

Examples 1-5, Comparative Examples 1-4 For each 140 parts by weight of EP rubber, each of the resins obtained in the above-mentioned Synthesis Examples 1-5 and Comparative Synthesis Example and the control resin was used.
Using parts by weight and the other ingredients shown in Table 1 and kneading with a low mill at a roll temperature of 120 ° C., a sheet-shaped unvulcanized rubber was obtained. The windability of the unvulcanized rubber on the roll during preparation of the unvulcanized rubber and the adhesive force of the obtained unvulcanized rubber sheet were examined.

Next, the vulcanization rate at 160 ° C. was measured using this unvulcanized rubber.

Further, using a press, 160 ℃ × 10 minutes, 100kg / cm ²
The vulcanized rubber was vulcanized under the conditions of
% Modulus and heat resistance were measured. The above results are shown in Table 1. The results when no resin was added are also shown in Table 1 for comparison.

Physical property test i) Roll winding property: The winding state on the roll mill at the time of preparing unvulcanized rubber was observed.

× Remarkably poor, △ poor, ○ good ii) Adhesive strength: Measured with "Pykuma tester" manufactured by Toyo Seiki.

The measurement conditions are a temperature of 25 ° C., a load of 500 g, a contact time of 30 seconds, and a peeling speed of 100 mm / min.

iii) Vulcanization speed; Toyo Seiki "Oscillating Disc Rheometer"
Was measured using. The vulcanization temperature is 160 ° C. The vulcanizing rate was shown by the difference between _{t 10} and _{t 90.}

t ₁₀ ; time (sec) until showing 10% of maximum torque t ₉₀ ; time (sec) until showing 90% of maximum torque iv) hardness; measured by Shore A according to JIS K-6301 did.

v) 300% modulus; measured using a No. 3 dumbbell in accordance with JIS K-6301.

vi) Heat resistance: After being left at 150 ° C. for 3 days, the 300% modulus was measured and shown as a ratio to the 300% modulus before heat deterioration.

EFFECTS OF THE INVENTION As shown in Table 1, the rubber composition obtained by blending the EP rubber with the phenolic hydroxyl group-containing cyclopentadiene resin described in the present invention is not vulcanized without significantly decreasing the vulcanization rate and the physical properties after vulcanization. Roll wrapping property and tackiness in the vulcanized state are greatly improved.

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Claims (1)

[Claims] 1. A general formula based on 100 parts by weight of a rubber-like polymer composed of ethylene and α-olefin and / or non-conjugated diene. (In the formula, H represents hydrogen, R represents an alkyl group having 1 to 3 carbon atoms, m and n are 0 or an integer of 1 or more, and m + n =
A 5-membered ring compound having a conjugated double bond represented by
Or its Diels-Alder adduct (component A) 10
0 parts by weight and at least one (component B) selected from monohydric and polyhydric phenols and their alkyl-substituted compounds 2 to
0.5 to 0.5 parts by weight of a phenolic hydroxyl group-containing cyclopentadiene resin obtained by copolymerization with 200 parts by weight of
A rubber composition comprising 30 parts by weight.