JPH1180426A - Nitrile-group-containing highly saturated rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition which in the state of a unvulcanized rubber sheet lowly anisotropic in strengths and not suffering from plasticizer bleeding by compounding a nitrile-group-containing highly saturated rubber with a white reinforcing filler and a chlorinated paraffin. SOLUTION: A rubber composition prepared by compounding 100 pts.wt. nitrile-group-containing highly saturated rubber with 100-600 pts.wt. white reinforcing filler such as silica or clay and 10-200 pts.wt. chlorinated paraffin is further compounded with sulfur or a sulfur-donating compound, an activator such as an amine, a vulcanization aid such as zinc white and a vulcanization accelerator such as thiazole to obtain a composition for vulcanized rubbers. The nitrile-group-containing highly saturated rubber a rubbery copolymer of (meth)acrylonitrile with butadiene or the like, having a content of an unsaturated nitrile compound of 10-60 wt.%, an iodine value of 60 or below, and a Mooney viscosity (ML1+4 , 100 deg.C) of 20-150. The chlorinated paraffin has a chlorine content of 40-75 wt.%, is represented by for example the chemical formula: C12 H22.4 Cl3.6 or C14 H25.9 Cl4.1 and is obtained by chlorinating an n-paraffin or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitrile group-containing highly saturated rubber composition having improved processability, which is suitable for general rubber applications such as a rubber plate and a cushion material and for forming a support for a road marking sheet material.

[0002]

2. Description of the Related Art In recent years, highly saturated rubbers containing nitrile groups, for example, hydrogenated acrylonitrile-butadiene copolymer rubber (H-NBR), have been used for a wide range of applications as heat-resistant and high-strength rubbers. However, H-NBR is harder than NBR, which is an unsaturated rubber containing a nitrile group, and the workability is not always good. Therefore, for example, a rubber composition in which a reinforcing filler is blended at a high concentration in H-NBR In the case of producing, it is usually necessary to incorporate a large amount of a plasticizer. Therefore, there is a problem that the hardness of the rubber composition is extremely reduced and high strength characteristics cannot be obtained. In addition, the plasticizer bleeds on the surface of the vulcanized rubber product such as a rubber plate, causing stains on the rubber product.

[0003] On the other hand, as a use of a composition in which a large amount of a white filler or the like is blended with H-NBR, there is a use of a road marking sheet material support. For example, zinc methacrylate is graft-polymerized to H-NBR. The use of a material has been proposed (Japanese Patent Publication No. 7-501592). The characteristic of this material is that it exhibits a very high level of strength characteristics even in an unvulcanized state and can have the hardness required for the support, but on the other hand, the strength decreases greatly due to temperature changes, The bending property decreases, the difference in strength between the calendar direction and the direction perpendicular to the calendar direction is large (the strength is anisotropic), and it is necessary to mix reinforcing and filler at a high concentration. It has been found that the rubber composition has extremely poor processability such as calenderability, and it is extremely difficult to form a sheet having a predetermined thickness on a mass production scale.
Attempts have been made to blend NBR in order to improve calender moldability, but the decrease in strength characteristics due to temperature changes is even greater, and further improvement is required for the practical use of a road marking sheet consisting of a support made of this material. is necessary.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a nitrile group-containing highly saturated rubber composition containing a white reinforcing filler at a high concentration and having improved processability such as calender moldability. That is. Another object of the present invention is to provide a road marking sheet material support. The present inventors have conducted intensive studies to achieve the above object, and as a result, by using chlorinated paraffin as a plasticizer,
It has been found that the obtained rubber composition can be subjected to calender molding, has low anisotropy in the strength of the unvulcanized sheet, and can be obtained as a rubber composition in which the plasticizer does not bleed.

[0005]

According to the present invention,
There is provided a nitrile group-containing highly saturated rubber composition comprising a nitrile group-containing highly saturated rubber and a white reinforcing filler and chlorinated paraffin. Further, according to the present invention, there is provided a road marking sheet material support formed from the above nitrile group-containing highly saturated rubber composition.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention. The nitrile group-containing highly saturated rubber used in the present invention includes a nitrile group-containing unsaturated compound such as acrylonitrile and methacrylonitrile and 1,3-butadiene, 2-methyl-1,3-butadiene, 1,3-pentadiene, Copolymer rubber with at least one conjugated diene-based monomer such as 2-chloro-1,3-butadiene, a nitrile group-containing unsaturated compound, a conjugated diene-based monomer, and another monomer copolymerizable therewith. The double bond of the conjugated diene monomer unit of the copolymer rubber obtained by copolymerizing the monomer is hydrogenated using a usual hydrogenation catalyst.

The other monomers include, for example, unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid and itaconic acid; methyl (meth) acrylate, ethyl (meth) acrylate, butyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, dimethyl maleate, diethyl fumarate, di-n-butyl fumarate, di-itaconate
alkyl esters of unsaturated carboxylic acids such as n-butyl;
Alkoxyalkyl acrylates of unsaturated carboxylic acids such as methoxy acrylate, ethoxy acrylate, methoxy ethoxy ethyl acrylate; 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth)
Having a hydroxyalkyl group such as acrylic acid (meth)
Acrylate; glycidyl (meth) acrylate; (meth) acrylamide such as (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide and derivatives thereof; α, β-
Acrylates having a cyanoalkyl group such as cyanoethyl acrylate, α, β and γ-cyanopropyl acrylate, cyanobutyl acrylate; acrylates having an amino group such as dimethylaminomethyl acrylate and diethylaminomethyl acrylate; trifluoroethyl acrylate, pentafluoropropyl acrylate;
Examples thereof include acrylates having a fluoroalkyl group such as dodecafluoroheptyl acrylate. At least one of these is used in an amount of about 0.1 to 15% by weight in the copolymer.

The content of the unsaturated nitrile compound in the nitrile group-containing highly saturated rubber is usually 10 to 60% by weight, preferably 20 to 50% by weight, the iodine value is usually 60 or less, preferably 30 or less, and the Mooney viscosity ( (ML _{1 + 4} , 100 ℃)
Is usually in the range of 20 to 150, preferably 60 to 90.

As the white reinforcing filler used in the present invention, any of those conventionally used for producing white rubber products can be used and is not particularly limited. For example, silicas such as anhydrous silicic acid, hydrous silicic acid, synthetic silicic acid, and colloidal silica; basic magnesium carbonate; activated calcium carbonate, calcium carbonate; hydrated magnesium silicate such as talc and finely divided magnesium silicate; clay, titanium oxide And these can be used alone or in combination of two or more. Among them, talc and silicas are preferred.

[0010] The amount of the white reinforcing filler used is not particularly limited, and is determined together with the type so as to satisfy required performances such as strength and hardness. The amount used is usually 1 to 100 parts by weight of the nitrile group-containing highly saturated rubber.
The proportion is from 00 to 600 parts by weight, preferably from 150 to 500 parts by weight.

The nitrile group-containing highly saturated rubber composition of the present invention may optionally contain carbon black. There are three types of carbon black, channel black, furnace black and thermal black, depending on the production method, and each of them has further various grades depending on the average particle size, oil absorption and the like. The type and amount of carbon black are not particularly limited, and are determined so as to satisfy the purpose of use and required performance of the rubber composition.

A particularly important component in the rubber composition of the present invention is chlorinated paraffin. By using chlorinated paraffin, it becomes possible to produce a rubber composition in which a high-concentration white reinforcing filler is blended with a nitrile group-containing highly saturated rubber, and calender molding of the obtained rubber composition becomes possible. The chlorinated paraffin used in the present invention has a chemical formula of C ₁₂ H _22.4 Cl.
_{3.6, C 14 H 24 C 6} , C 14 H 25.9 Cl 4.1, C 26 H 31.1
It is obtained by chlorinating paraffin wax or n-paraffin represented by Cl _22.9 or the like, and various products are commercially available depending on the degree of chlorination, and any of them can be used. Chlorinated paraffins have high compatibility with nitrile group-containing highly saturated rubbers and do not bleed even when used in large amounts.

Preferred chlorinated paraffins have a chlorine content of 40 to 75% by weight. The amount of the chlorinated paraffin is usually 10 to 200 parts by weight, preferably 60 to 150 parts by weight, based on 100 parts by weight of the nitrile group-containing highly saturated rubber. The optimum amount of use is determined in consideration of the balance with other characteristics such as ease of use, strength characteristics and hardness.

The rubber composition of the present invention can be produced by mixing a nitrile group-containing highly saturated rubber with the above-mentioned components using a conventional mixer such as a roll, kneader, Banbury mixer or the like. At that time, additives such as a processing aid such as stearic acid, an antioxidant, and an ultraviolet stabilizer can be added as necessary.

When a vulcanized rubber product is produced using the nitrile group-containing highly saturated rubber composition of the present invention, a vulcanizing agent is added to the rubber composition. As the vulcanizing agent to be used, any vulcanizing agent conventionally used in nitrile group-containing highly saturated rubbers such as sulfur or sulfur donating compound, organic peroxide can be used, and is particularly limited. Not something. When a sulfur-based vulcanizing agent such as sulfur or a sulfur-donating compound such as tetramethylthiuram disulfide is used as a vulcanizing agent, activators such as stearic acid and amines, vulcanizing aids such as zinc white, guanidine , A thiazole-based, a thiourea-based, a thiuram-based, a dithiocarbamate-based, a xanthate-based vulcanization accelerator, and the like. When an organic peroxide is used as a vulcanizing agent, triallyl isocyanurate,
A crosslinking aid such as trimethylolpropane trimethacrylate is blended. The amount of the vulcanizing agent to be used is not particularly limited, and may be determined so as to satisfy the purpose of use and required performance of the rubber composition of the present invention. Usually, sulfur or sulfur-donating property is relative to 100 parts by weight of rubber. The compound is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and in the case of an organic peroxide, 0.01 to 15 parts by weight, preferably 0.05 to 5 parts by weight.
10 parts by weight. In the present invention, at least one of a nitrile group-containing highly saturated rubber and a vinyl chloride resin, NBR, EPM, EPDM, acrylic rubber, epichlorohydrin rubber or the like is used as long as the gist of the present invention is not impaired.
Seeds can be mixed and used.

Further, the nitrile group-containing highly saturated rubber composition of the present invention can be used for a road marking sheet material support in an unvulcanized state without adding a vulcanizing agent. In general, a road marking sheet material needs to be adhered following irregularities on a road surface, and therefore, a soft vinyl chloride resin or rubber has been conventionally used as a material for forming a support. Normal,
As a road marking sheet material, a rubber composition containing a white reinforcing filler mainly composed of rubber is 1 to 1.5 mm on a calendar.
A sheet or tape in which a surface layer made of a polyurethane resin or an epoxy resin colored with a white pigment or the like is formed on the surface thereof, and a pressure-sensitive adhesive is applied to the back surface, is used as a support that is formed into a sheet of about a degree. . Since such road marking sheet material is extremely easy to construct, it is affixed flexibly to a predetermined place such as a road or a parking lot, and when unnecessary, is peeled off from the road and discarded.

Since the support needs to follow the road surface, the rubber composition is used in an unvulcanized state. In addition, the life of the road marking sheet material depends on the support, and the road marking sheet material must be able to withstand the load even if an automobile or the like constantly runs on it and be able to withstand long-term use without breaking. The strength is required for the support together with the surface layer, and the strength is increased or decreased by the temperature (for example,
(Summer and winter) It is necessary that no cracks occur.
It is also necessary that the material be able to follow the thermal expansion and contraction of a road or the like.

When the nitrile group-containing highly saturated rubber composition of the present invention is used as a support for a road marking sheet material, the amount of the white reinforcing filler used depends on the hardness (JIS A) of the obtained unvulcanized sheet. Hardness) is 80 to 95 and the whiteness (Y
Value) is preferably 80 or more, more preferably 100 to 600 parts by weight, more preferably 150 to 500 parts by weight, per 100 parts by weight of the nitrile group-containing highly saturated rubber. If the amount used is less than 100 parts by weight, the hardness and whiteness are insufficient, and if it exceeds 600 parts by weight, the calenderability deteriorates, and it is difficult to form a sheet having a predetermined thickness. The chlorinated paraffin is the same as described above.

When the nitrile group-containing highly saturated rubber composition of the present invention is used as a support for a road marking sheet material, chlorinated paraffin does not bleed on the surface of the support, and the calender of the rubber composition is used. Formability can be improved and sheets of various thicknesses can be manufactured. Furthermore, the use of chlorinated paraffin enhances the light reflectivity of the support and prevents bleeding, thereby preventing the support from being contaminated by sand or gravel.

A road marking sheet material support using the rubber composition of the present invention is produced by molding the rubber composition into a sheet having a predetermined thickness by a calender. The characteristics of the support obtained by the rubber composition of the present invention include a hardness (JIS A) of 80 to 95 and a tensile strength of 80 to 200 k.
g / cm ² , elongation 80 to ²⁰⁰ %, anisotropy of tensile strength (tensile strength in the grain direction (direction of releasing a sheet such as a roll) / anti-grain direction (direction perpendicular to the sheet releasing direction)) Tensile strength) is 0.8 or more, whiteness (Y value) is 80 or more,
It can be bent at a low temperature of 180 degrees at -15 ° C.

[0021]

Next, the present invention will be described specifically with reference to examples and comparative examples. Unless otherwise specified, parts and percentages below are by weight.

Examples 1 and 2, Comparative Examples 1 to 3 Hydrogenated acrylonitrile-butadiene copolymer rubber (hydrogenated NBR) (Zetpol 2010, manufactured by Zeon Corporation; acrylonitrile content 36%, as a nitrile group-containing highly saturated rubber) Iodine value 11, Mooney viscosity (ML _{1 + 4} ,
100 ° C) 85) and acrylonitrile-butadiene copolymer rubber (NBR) as an unsaturated rubber having a nitrile group.
(Nipol DN201 manufactured by Zeon Corporation: acrylonitrile content: 33.5%, Mooney viscosity: 78) and Table 1
The rubber and each compounding agent were mixed with an 8-inch roll (roll temperature: about 80 ° C.) to prepare a rubber composition according to the compounding recipe shown in (1). In the same manner, a rubber composition using ZSC2299 manufactured by Zeon Corporation, in which hydrogenated NBR was graft-polymerized with zinc methacrylate, was prepared. Each of the obtained rubber compositions was evaluated for calender moldability, sheet strength characteristics, and the like by the following test methods. Table 1 shows the results.

(1) Calender moldability Each of the above rubber compositions is prepared into a vertical calender (three rolls).
, And calender moldability was evaluated. The case where the sheet was formed without any problem was indicated as “good”, and the case where the rubber composition was stuck to the calender and the sheet could not be formed, or the case where it took a long time, was indicated as “impossible”.

(2) Evaluation of mechanical strength characteristics A sheet having a thickness of about 1 mm was prepared using a calender,
Strength characteristics were measured at room temperature and 50 ° C. according to K6301. The anisotropy of the tensile strength was determined by the following formula from the tensile strength measured at room temperature by preparing test pieces punched out of the sheet in parallel and at right angles to the calender direction. The larger the value, the smaller the anisotropy. Anisotropy of tensile strength (%) = [(tensile strength of test piece perpendicular to calender) / (tensile strength of test piece parallel to calender)] × 100

(3) Permanent elongation As a measure of the ability of the support to follow the road surface, the elongation is determined by JIS K
It was measured according to 6301. (4) 180 ° Bendability at Low Temperature A strip-shaped test piece was bent in a constant temperature room controlled at 0 ° C., −5 ° C., and −15 ° C., and it was evaluated whether it could be bent at 180 °. The case where bending was possible without any problem was indicated as "OK", and the case where the sheet was broken or cracked was indicated as "NO". (5) Whiteness (Y value) The whiteness of the calendered sheet was measured using a spectrophotometer. (6) Bleed resistance The sheet was left standing in an oven at 80 ° C. for 24 hours and evaluated with stickiness by touching the surface. When no stickiness was observed, “good” was given, and stickiness was observed. Is indicated as "poor".

The results in Table 1 show that the rubber composition of the present invention using hydrogenated NBR (Examples 1 and 2) has excellent calender moldability. It also shows that the anisotropy in tensile strength is low and that it has a high level of tensile strength and elongation even at room temperature and at 50 ° C. On the other hand, Comparative Examples 1 and 2 (in which hydrogenated NBR was graft-polymerized with zinc methacrylate) could not be formed into a sheet by a calender, had a large anisotropy in tensile strength, and had a room temperature and 50 ° C. It shows that the changes in tensile strength and elongation are large.

In Comparative Example 3 (using hydrogenated NBR) using DOP as a plasticizer, the mixture was not rolled up on a roll and chlorinated paraffin was used until a good rubber composition was obtained ( About three times as long as in Example) was required. Furthermore, the bleeding resistance is good without the plasticizer oozing out on the sheet surface using the rubber composition of the present invention.

[0028]

[Table 1] (Note) (* 1) Empara 70 manufactured by Ajinomoto Co.

[0029]

According to the present invention described above, a reinforcing / filling agent can be compounded in a high concentration, and the obtained rubber composition can be calendered. A rubber composition having low anisotropy and having good strength properties and low-temperature bending properties is provided. Further, the rubber composition of the present invention has good bleeding resistance.
Therefore, the rubber composition of the present invention is suitable for use in an unvulcanized state, for example, for manufacturing a support for a road marking sheet material, a cushion material for receiving falling objects used at a construction site, a caulking material, and the like. .

Preferred embodiments of the invention are as follows. (1) The nitrile group-containing highly saturated rubber has an acrylonitrile content of 10 to 60% by weight. The hydrogenated NBR is preferably 20 to 50% by weight and has an iodine value of 60 or less, preferably 30 or less. (2) 100 to 600 parts by weight, preferably 150 to 500 parts by weight, of a white reinforcing filler is blended with 100 parts by weight of the nitrile group-containing highly saturated rubber. (3) Chlorinated paraffin is blended in an amount of 10 to 200 parts by weight, preferably 60 to 150 parts by weight, based on 100 parts by weight of the nitrile group-containing highly saturated rubber. (4) The chlorinated paraffin has a chlorine content of 40 to 75% by weight.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C08J 5/18 CEQ C08J 5/18 CEQ

Claims (2)

[Claims] 1. A highly saturated nitrile group-containing rubber composition comprising a nitrile group-containing highly saturated rubber and a white reinforcing filler and chlorinated paraffin. 2. A road marking sheet material support formed from the nitrile group-containing highly saturated rubber composition according to claim 1.