JPS58225138A - Highly rigid rubber composition - Google Patents

Abstract

PURPOSE:To obtain titled rubber composition giving high resilience when impacted at high speed, suitable for golf balls, by the use of a polybutadiene having a specific average sequence of 1,4-bond. CONSTITUTION:A rubber composition comprising (A) 50-100 (pref. 80-100) pts.wt. of a polybutadiene having >=80wt% of cis-1,4-bond whose average sequence is >=110 and (B) 50-0 (pfer. 20-0)pts.wt. of a diene rubber is incorporated with (C) a crosslinkable monomer (pref. a methacrylic monoester), (D) an inorganic filler (pref. zinc oxide), and (E) an organic peroxide (pref. dicumyl peroxide) thus obtaining the objective curable rubber composition. Said polybutadiene can be produced using a lanthanum series rare earth metal compound- based catalyst, preferably giving a Mooney viscosity (ML1+4 at 100 deg.C) of 20-50.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high hardness rubber composition with excellent resilience containing polybutadiene, preferably a high hardness rubber composition containing polybutadiene as a main component using a catalyst based on a lanthanum series rare earth element compound.

Recently, since sweet-acid polymer substances have begun to be actively used as materials for golf poles, the golf ball structure has come to be dominated by No. 17 de Gaulle rather than thread-wound balls. The functions of these golf balls include flight distance, controllability, durability, and feel at impact, but in particular, they aim to increase flight distance in the high hitting speed range, that is, improve the ball's resilience and increase the initial velocity of the ball. Increasing this is an important issue in ball design technology. In response to these demands, taking advantage of its high resilience,
Although polybutadiene rubber compositions have been used, it has been desired to further improve the resilience in the high impact speed range.

As a result of intensive research to improve resilience in the high impact speed range, the inventors of the present invention found that polybutadiene rubber with a specific average chain length of 1.4 times provides a rubber composition with excellent resilience. They discovered this and arrived at the present invention.

According to the invention, the cis-1,4 linkage content is at least 8
Polybutadiene rubber having a strength of 0.0 and an average chain length of 1,4 bonds of 100 or more, 50 to 100. A rubber composition consisting of 50 to 0 quintillion parts of diene rubber, a crosslinking monomer, an inorganic filler, and a shoulder compound as essential components, which has excellent resilience in the high impact speed range. A vulcanizable high hardness rubber composition is provided.

The average chain length of 1 and 4 bonds defined in the present invention is determined as follows. That is, the hydrogenated product of polybutadiene of the present invention to be tested is hydrogenated polybutadiene with H, J, Har
wood, Makromol, Ch@m, , 1
63.1 (1973) according to the method described.
It is obtained by complete hydrogenation of nyl hydrazide in p-F fluorene. Complete hydrogenation is confirmed by H'-NMR. Hydrogenated polybutadiene is manufactured by Nippon Miko FX-
Measurement is performed using a 100-inch NMR device under the conditions described in F.

Sample 1! degree = 300 Cape/2-11.2.4-trichlorobenzene, 10mφ13C-NMR dedicated glove, observation frequency: 25.05MHz, internal locking method observation pulse width: 45° 6μsec.

Pulse repetition time: 5.0 sec, Spectral width: 2KHz.

Measurement temperature: 125°C, internal standard: HMD8. 4 Number of calculations: 110 x 100 to 190 x 100 times, and analysis by J, C, Randall, J, Poly
m, set,.

Polymer Phyalas Editlon
13.1975 (1975).

・,j Here, I1% 111% I@, I,, I I(+
, III have chemical shifts of 37.2.34.8, respectively.
．． 34.0.31.0.30, 5.30.0 ppm are the area intensities of the peaks.

Further, the heat of fusion of the polybutadiene hydrogenation product of the present invention corresponds to an average chain length of 1.4 bonds, and is preferably 42 Cat/f or more. This was done by using a differential scanning calorimeter [manufactured by DSC Rigaku Denki ■] and placing about 1011 V of hydrogenated polybutadiene in an aluminum pan for measurement. Measurement is performed at a heating rate of 10° C./min.

Determine the amount of heat from the melting peak area. Heat of fusion is 42Cs
If it is less than 14/f, the 1,4-linked average chain length will not be 110 or more.

The amount of dowry gold is determined using a nuclear magnetic resonance apparatus.

The polybutadiene rubber having a specific average chain length of 1.4 used in the present invention is preferably an adduct of a lanthanum series rare earth element (hereinafter referred to as a Ln compound), an organoaluminum adduct, a Lewis acid, or a Lewis base. From the group of
: It can be produced by polymerizing butadiene in the presence of a catalyst.

As the Ln adduct, halides, carmenates, alcoholades, thioalcolades, amides, etc. of metals having an atomic number of 57 to 71 are used.

The organoaluminum has the general formula AtR, R, R, (where %R1 to R3 are hydrogen or a hydrocarbon group of CI-C, and %R1 to R3 may be the same or different. (good) is used.

The Lewis acid has the general formula AtXnR3-H (where,
X is a halogen, R is a hydrocarbon residue, n=1
．． 1.5.2.3) or other metal halides are used.

Lewis bases are used to solubilize Ln compounds in organic solvents, and suitable examples include acetylacetone, ketones, and the like. Butadiene/Ln compound °f ratio"Q 5
X 10 ~°゛°・1 preferably 10
~10.

AtRIRIRI/Ln compound has a molar ratio of 5 to 5o
o, preferably lO~300. The molar ratio of the halide/Ln compound in the Lewis acid ranges from 1.0 to 1O1, preferably from 1.5 to 5. The molar ratio of Lewis base/Ln adduct is 0.5 or more, preferably 1 to 20.

The method for producing the above catalyst is described in detail in Japanese Patent Application No. 56-99684.

The Ln adduct catalyst is a solvent f during the polymerization of butadiene.
It can also be used in a bath-dissolved state or supported on madanesia, magnesium monoxide, etc.

Bulk polymerization may be carried out using a solvent at or without using a solvent. Polymerization temperature is usually -30℃~1
The temperature is 50°C, preferably 10 to 80°C, and the polymerization pressure can be carefully selected depending on the conditions.

In the present invention, the average length of 1.4 bonds is 110 or more, preferably 110 to 530, more preferably 130 to 53
It is in the range of 0. If it is smaller than 110, there is no effect of improving resilience or initial velocity.

The polybutadiene of the present invention can also be obtained by mixing polybutadienes having different average chain lengths of 1.4.

The content of cis-1,4 linkages in the polybutadiene rubber of the present invention is at least 80, preferably 901 or more. If the content of cis-1,4 bonds is less than 80%, the resilience improving effect disappears. Mooney viscosity of polybutadiene
l is not particularly limited, but ML1+, (100°C)2
0-150 is preferable.

Examples of the diene rubber used in the present invention include natural rubber, polyisoprene rubber, and styrene-butadiene/copolymer rubber.

In the rubber composition of the present invention, the blend ratio of the polybutadiene rubber and diene rubber is 50 to 100 parts by weight to 50 to 0 parts by weight, preferably 80 to 100 parts by weight to 20 parts by weight.
~O1 parts by weight.

If the amount of polybutadiene rubber is less than 50 parts by weight, there is no effect of improving resilience or initial velocity.

The high hardness rubber composition of the present invention is a rubber composition formed by blending a C crosslinkable monomer, an inorganic filler, and an organic peroxide as essential components in the composition of the polybutadiene rubber and diene rubber. be.

According to the present invention, a high hardness rubber composition having excellent resilience in a high impact speed region can be obtained.

The crosslinking monomers used in the present invention include α, β-
It is an ethylenically unsaturated monocaldenic acid or a monoester of dicargenic acid or dicameponic acid. Specifically, acids such as methacrylic acid, acrylic acid, ethacrylic acid, cinnamic acid, crotonic acid, rubic acid, maleic acid, phthalic acid and itaconic acid, and dicalde 71 (i.e. maleic acid, itaconic acid and phthalic acid). , ) is a monoester of Preferred is methacrylic acid. The blending amount is preferably 10 to 50 parts by weight per 100 parts by weight of the polymer.

The inorganic thickening agent used in the present invention is an additive that neutralizes the carboxylic acid groups present in the heavy crosslinking monomer and has the function of becoming a sharp ion storage body and adjusting the weight of the crosslinked product. It is.

Examples include titanium oxide, chlorinated lead, iron oxide, chlorinated aluminum, calcium oxide, calcium hydroxide, and salivary lead carbonate, with salivary lead oxide being preferred. The composition of the inorganic filler is 20 to 8 parts by weight of the polymer.
0 parts by weight is preferred. The portion of the inorganic filler that plays a role in adjusting the end of the crosslinked product may be replaced with a known filler such as barium sulfate, phosphoric acid, clay, carbine black, carbonic acid, or a mixture thereof. I do not care.

In order to crosslink and cure the mixed material of the present invention, an organic peroxide is added as a crosslinking agent.
(t-butylperoquine improvil)benzene, 1.
Examples include 1-di-t-butylperoxy-3,3,5-)limethylcyclohexane, and dicumyl peroxide is preferred. The amount of organic peroxide to be distributed is preferably 10.5 to 8 parts by weight per 100 parts by weight of the polymer.

■ As a method for obtaining high hardness rubber from polybutadiene, a crosslinkable monomer, an inorganic filler, and an organic peroxide according to the present invention, first, polybutadiene and an inorganic filler are mixed using an open roll, Nokunoku Lee, Kneader 1 extruder, etc. Mix together, add the crosslinking monomer to Part 1, and knead thoroughly.

Next, an organic peroxide is added to this mixture while kneading it on a roll to obtain a blend. The kneaded handout was placed in a mold at a crosslinking temperature of 120' to 180°C and a crosslinking time of 5 to 45°C.
Mold for minutes.

The cross-linked and molded high-hardness rubber composition 1 of the present invention has excellent resilience in the main high-impact velocity range, so it can be suitably used in applications that take advantage of this feature, particularly as a material for solid golf soles.

Next, the present invention will be further explained with reference to Examples.The present invention is not limited thereto unless it goes beyond the gist of the present invention.

[Examples 1 to 5] In a sufficiently dried 5-t glass autoclave, 2.5 to 9 parts of cyclohexane were charged under nitrogen, then 0.5 Kf of butadiene was charged, and the temperature was raised to 60°C. Tri'ethylaluminum 138.9mM.

Dienal aluminum bromide 2.31mM and neodymium octenoate 0.926mM and acetylacetone 1
．． The entire amount of the catalyst prepared by aging the reaction product with 85 mM of phytadiene in a separate container in the presence of 0.1 F of phytadiene was charged, and weighting was started.

A conversion rate of 100% was reached after 2 hours of polymerization. At this point, a methanol bath solution 5- containing an antioxidant 2.6-sheet@rt and butyl cresol was injected to stop the reaction.

After steam stripping according to a conventional method, it was dried with a 1 ioc hot roll to obtain polyptadiene.

Table 1 shows the average chain lengths of 1,4 linkages, microstructures and calorimetric measurements of various polybutadiene samples.

Polybutadiene sample A1 in Table 1 is Italian A
This is a uranium-catalyzed polybutadiene rubber manufactured by NIE. Sample/f A2 is prepared by dissolving sample/I61 and sample 4 in n-hexane at the same concentration (heavy [1]).
It was obtained by blending at a ratio of 1:40 and drying. Sample A5 is sample A4 and sample /P66, respectively.
Dissolved in hexane to the same concentration (wt%), 1:4
It was obtained by blending at a ratio of 0 and drying. Sample flat 6
is polybutadiene (manufactured by Japan Synthetic Rubber, product name BRO1)
). Sanfol/167 is bolibutadiene (manufactured by Ube Industries, trade name: Ube Ball 150).

Sample &8 is polybutadiene (manufactured by Nippon Tsusei Rubber Co., Ltd., trade name BRO2). Sample A9 is polybutadiene (manufactured by Philips Chemical Company, trade name Cl).
8-41203).

The sample grave 10 is made of polybutadiene (manufactured by Asahi Kasei ■, trade name DIENg 35NF). Sample A3 is created using the same operation as sample black 2, and sample AI and sample A
4 in a ratio of 4 to 6 and dried.

Table 1 Note) Heat of fusion i) (cat/f) was determined from the hydrogenated sample.

Juice distribution formula (for one-piece golf pole l'1ll) Polybutadiene rubber 1oo (-i1 part) Sacrificial lead flower
42 Methacrylic acid 20 Permil D 2.8 Nippon Oil & Fats ■ (Dicumyl peroxide) Vulcanization conditions: 150° C., 30 minutes The vulcanization properties of the rubber distribution composition were measured, and the results are shown in Table 2.

In addition, in the case of distribution for two-piece golf, the sacrificial lead vehicle used is 30 parts by weight for the core of a large ball, and 5 parts by weight for the core of a small sole, but the present invention is applicable to both distributions. The characteristics of the product are not impaired.

In Table 2; (1) Hardness was measured according to JIS K6301.

(2) Loss tangent (tanJ), which is an index of resilience in the high impact speed range, was determined using a viscoelastic spectrometer (RMB type, manufactured by Rheometrics). The smaller the value, the better.

Resilience was measured using a Dunlop Tripenmeter.

(3) Use the same rotating disc type as the one used in U8GA.

Head speed 1143.0±0.3 Cm 7 seconds) [Example 6
~7] In Examples 6 and 7, the results of measurements made by changing the type of diene rubber are shown in Table 3.

Table 2 (2) (1) tanJ long? 2□K (at25Q 工ゆ工r example pull, 18 touz) [R,T]'
K-6301 (1) (m7 seconds) -19031
8361,2 #-290308361,4 #-390288461,6 #-491288361,6 #-592318361,3-693378260,5 #-794398260,4 #-896477859,6 #-996487859,5 #-10 96787057,6 Table 3 (1) R88 So1 (2) Made of Japanese synthetic rubber ■

Claims (2)

[Claims] (1) A composition consisting of 50 to 100 parts by weight of polybutadiene containing at least 80 cis-1,4 bonds and having an average chain length of 1,4 bonds of 110 or more and 50 to 0 parts by weight of diene rubber. A vulcanizable high-hardness rubber composition comprising a crosslinking monomer, an inorganic filler, and an organic peroxide as essential components. (2) High hardness according to claim (1), wherein the polybutadiene rubber is mainly composed of polybutadiene rubber obtained using a lanthanum series rare earth element adduct catalyst. Rubber composition.