JPH02133340A - Glass fiber for reinforcing rubber - Google Patents

Abstract

PURPOSE:To improve the bonding strength of glass fibers to rubber by successively treating the glass fibers with rubber latex contg. dispersed resorcin- formaldehyde resin and nitrile rubber, etc., to fit the fibers to the matrix of the rubber to be reinforced. CONSTITUTION:Rubber latex contg. dispersed resorcin-formaldehyde resin is prepd. as a first liq. and a second liq. contg. nitrile rubber or hydrogenated nitrile rubber and isocyanate is also prepd. Glass fibers are fitted to the matrix of rubber to be reinforced by successive treatment with the first and second liqs.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to rubber reinforcing glass fibers used for reinforcing various rubber products, and more specifically, to a unique method for better adhesion between glass fibers and rubber. This relates to surface-treated glass fibers.

[Prior Art] Rubber products such as rubber belts and tires are widely reinforced with glass fibers in order to improve their strength, toughness, dimensional stability, etc. However, in these applications, they are subjected to repeated bending stress, resulting in bending fatigue, resulting in decreased performance, and peeling between the glass fiber and the rubber matrix is likely to occur.

In order to prevent this peeling and the deterioration of performance, it is necessary to increase the compatibility and adhesive strength between the glass fiber and the rubber matrix, and various treatment agents have been proposed to be applied to the surface of the glass fiber. The most common method is to use a dispersion of resorcinol/formaldehyde resin and various latexes. However, in various applications, rubber materials with higher physical properties are being used. After the treatment, various methods have been proposed in which treatment is performed using different chemicals. For example, JP-A-63126975 discloses that after treatment with a first liquid containing a terpolymer latex of vinyl pyridine-styrene-butadiene, rubber latex, and a water-soluble condensate of resorcinol-formaldehyde,
A method of treatment with a second liquid containing a halogen-containing polymer, incyanate, is shown. However, even in this case, the adhesive strength is not necessarily sufficient, and this tendency is particularly strong when hydrogenated nitrile rubber or the like is used as the rubber matrix.

[Means for Solving the Problems] In view of the problems of the prior art, the present inventors have arrived at the present invention as a result of intensive studies. That is, the present invention provides glass fibers for reinforcing rubber, which are treated with a first liquid consisting of a resorcinol-formaldehyde resin rubber latex dispersion and then treated with a second liquid containing nitrile rubber or hydrogenated nitrile rubber and an isocyanate. As the first liquid used in the present invention, a commonly used resorcinol-formaldehyde resin rubber latex may be used, but it is more preferable to use vinylpyridine-styrene-butadiene (vinylpyridine-styrene-butadiene) as the rubber latex. VP/styrene-butadiene rubber (hereinafter referred to as SBR), VP/natural rubber (hereinafter referred to as NR), VP/carboxylated SBR (hereinafter referred to as C-3BR)
), ■P/carboxylated nitrile rubber (hereinafter referred to as C
-NBR), VP/butadiene rubber (hereinafter referred to as BR), etc. are used.

The weight of pure resorcinol and formaldehyde is preferably 15% by weight or less with respect to the solid weight of the rubber latex of the first liquid. In addition, it is preferable that the ratio of resorcinol and formaldehyde is 1:0.5 to 2.5. % range is preferable; if it is less than this range, the fatigue performance will not be sufficient, and if it exceeds this range, the adhesiveness will become unstable, which is not preferable. After this treatment, drying is usually performed at a temperature in the range of 200 to 350°C. .

The glass fibers thus prepared are further treated with a second liquid, but before treatment, as is generally done, the glass fiber bundles are first twisted, and then a plurality of fibers are tied together and roughly twisted. multiply. The components of the second liquid of the present invention include isocyanate and NBR or hydrogenated NBR, and examples of the isocyanate include methylene diphenyl diisocyanate, toluene diisocyanate, triphenylmethane triisocyanate, and naphthalene diisocyanate. Most preferred is methylene diphenyl diisocyanate, which has a film hardness of .

As NBR, various commercially available NBRs having a nitrile bond content ranging from 20 to 40% can be used. In the present invention, hydrogenated NBR can be used instead of NBR. By using this hydrogenated NBR, it has excellent adhesion and extremely good heat resistance, making it particularly suitable for applications requiring high heat resistance.The hydrogenated NBR used in the present invention has an unsaturation degree of 14.
It is preferable to have a degree of unsaturation in the range of 28 to 28. If the degree of unsaturation is lower than this, the heat resistance will be further improved, but the adhesiveness will be poor, which is not preferable.

Isocyanate and NBR or hydrogenated N in the present invention
The ratio of BR to isocyanate 1 is preferably in the range of 0.5 to 3. If the ratio is less than this range, the film will become too hard, and if it exceeds this range, the adhesion and adhesion will become unstable, which is not preferred. In addition, the amount of this isocyanate and NBR or hydrogenated NBR in the second liquid is 5 to 1 in solid form.
The amount is preferably in the range of 5% by weight; if it is less than this range, sufficient adhesive strength cannot be obtained, and if it exceeds this range, the adhesion becomes unstable, which is not preferred. Furthermore, in addition to these essential components, it is of course possible to add materials with excellent adhesive performance and film-forming ability, such as chlorinated rubber, to the second liquid, thereby making it possible to obtain a rubber reinforcing material with even higher adhesive strength. Furthermore, various commonly used additives such as zinc white, magnesium oxide, sulfur, and litharge can also be used as vulcanizing agents.

After treatment with the second liquid, drying is carried out, but the drying conditions are not particularly limited (-- boat fishing conditions, specifically,
The glass fiber used in the present invention is not particularly limited.
Usually, glass fibers with a thickness of 5 to 13 μm are coated with a sizing agent consisting of an anchor agent, an adhesive, a surfactant, etc.
A bundle of about 0.00 glass fibers is used.

Although the glass fibers treated according to the present invention can be used in various rubbers, the types of rubbers to be used are not particularly limited, and include heat-resistant rubbers such as hydrogenated NBR and chlorosulfonated polyethylene (hereinafter referred to as C3M) rubber. The glass fiber of the present invention exhibits its characteristics particularly when it is used for rubber having excellent properties.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Vinylpyridine, styrene and butadiene at 15:1
VP containing at a ratio of 5:70 (manufactured by Sumitomo Nogatta Co., Ltd.,
Contains 447 parts by weight (trade name: Vilatex, solid content 41% by weight), 195 parts by weight of SBR (2108 manufactured by Japan Synthetic Rubber Co., Ltd., solid content 40% by weight), and 6.7% by weight of an addition condensate of resorcinol and formaldehyde. A first liquid was prepared consisting of 320 parts by weight of the aqueous solution and 22 parts by weight of aqueous ammonia (25%). In addition, 36 parts by weight of polyisocyanate (manufactured by Mitsui Toatsu Co., Ltd., MDI-PH, metaphenylene diisocyanate type), 60 parts by weight of hydrogenated NBR compound (manufactured by Nippon Zeon Co., Ltd., 2020), and zinc oxide No. 3 1 as a vulcanizing agent. A second solution was prepared containing 891 parts by weight of a solvent consisting of acetic acid, methyl ethyl ketone, and toluene.

Three glass fiber bundles made of 200 glass fibers of 9 μm were aligned and treated with the first solution according to a conventional method. The solid content adhesion rate at this time was 19% by weight. 28
After drying at 0°C for 22 seconds, the glass fiber bundle was
A set of 13 fiber bundles that had been twisted 2.0 times per cm was then twisted 2.0 times per 2-2-54cm, and then treated with the second solution at 155°C.
Drying was performed for 48 seconds. The solid content adhesion rate by this second liquid treatment was 2.3% by weight. This product was used as a reinforcing fiber to create a composite with rubber and tested.

"L engineering J engineering ■ Hydrogenated nitrile rubber (manufactured by Nippon Zeon Co., Ltd., 2020) 1
00 parts by weight, carbon black HA F 50
parts by weight, 5 parts by weight of zinc white, 3 parts by weight of plasticizer, 2 parts by weight of anti-aging agent, and 3 parts by weight of vulcanization accelerator.

■Chlorosulfonated polyethylene (manufactured by Showa Denko/DuPont, 100 parts by weight of C3M405, carbon black SRF5 (73 parts of 3M, 5 parts by weight of magnesium oxide, 3 parts by weight of pentaerythol, 4 parts by weight of plasticizer, 3 parts by weight of anti-aging agent) The actual part contains 2 parts by weight of a vulcanization accelerator.

The test piece was a rubber sheet made of rubber ■ or ■ (3a+m
Thickness) 1.9 to 20 treated reinforcing fibers/25m+
*Narape, then cover with a cloth and heat at 150°C13
It was prepared by vulcanization molding at a pressure of 20 kg/c+J for 0 minutes.

When the peel strength of this test piece was measured, it was 18Kg/25mm for rubber ■, and 16K for rubber ■.
g/25ml. The peeling speed was 50 μ/min.

Examples 2 to 5, Comparative Examples 1 to 5 Peel strength was measured in the same manner as in Example 1, except that the first liquid in Example 1 was replaced with a treatment liquid having the following composition.

1L 131 parts of NR (IIA latex, solid content 60% by weight) was added instead of SBH in the first liquid of Example 1.

16 C-5BR (manufactured by Asahi Kasei Kogyo Co., Ltd., L-5702, solid content 48% by weight) was added instead of SBH in the first liquid of Example 1.
Added 4 parts by weight.

(-NBR (manufactured by Nippon Zeon Co., Ltd., Nirapol 1571, solid content 40% by weight) instead of SBR in the first liquid of Example 1
) was added in an amount of 195 parts by weight.

In place of SBR in the first liquid of Example 1, 91 parts by weight of BR (manufactured by Japan Synthetic Rubber Co., Ltd., 0700, solid content 57% by weight) was added.

Further, for comparison, the peel strength of the samples treated with the first liquid of Examples 1 to 5 but not treated with the second liquid was measured in the same manner. This result is the first
Shown in the table.

Example 6.7 The treatment was carried out in the same manner as in Example 4.5 except that the second liquid had the following composition, and the adhesive strength was measured.

The results are shown in Table 1.

In addition to No. 2M of Example 1, chlorinated rubber (manufactured by Asahi Denka Co., Ltd., CR
-5) was added in an amount of 12 parts by weight.

Examples 8 to 12 NBR compound (
The adhesive strength was measured in the same manner as in Examples 1 to 5, except that 1042 (manufactured by Nippon Zeon Co., Ltd.) was used. The results are shown in Table 1.

Example 13.14 NBR compound (
The adhesive strength was measured in the same manner as in Example 6.7, except that 1042 (manufactured by Nippon Zeon Co., Ltd.) was used. The results are shown in Table 1.

Table 1 [Effects of the invention] The reinforcing fiber according to the present invention is made of various rubbers, especially hydrogenated NBR.
It has excellent adhesion to heat-resistant rubbers such as chlorosulfonated polyethylene and can be used in a wide range of applications.

Patent applicant: Central Glass Co., Ltd.

Claims (1)

[Claims] A glass fiber for reinforcing rubber, characterized in that it is treated with a first liquid consisting of a resorcinol-formaldehyde resin rubber latex dispersion, and then treated with a second liquid containing nitrile rubber or hydrogenated nitrile rubber and an isocyanate.