JPH0967482A - Rubber compound, molded rubber article having urethane resin coating layer and production of the molded rubber article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber compound giving a molded rubber article having a urethane resin coating later in high adhesivity by compounding an ethylene- propylene rubber compound with a specific silane coupling agent. SOLUTION: A rubber compound of an ethylene-propylene rubber is compounded with a silane coupling agent of the formula (X is a univalent organic functional group; Y is a univalent hydrolyzable group) (preferably vinyltriethoxysilane, γ-glycidoxypropyl trimethoxysilane, etc.). It is preferable to compound exclusively an ethylene-propylene-diene terpolymer as the ethylene- propylene rubber of the rubber component. The rubber compound is usually further compounded with a reinforcing agent such as carbon black, a filler, a crosslinking agent, etc. The compounding of the silane coupling agent is preferably carried out by compound therewith a white filler surface-treated with the silane coupling agent to improve the miscibility and workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber compound, a rubber molded product and a method for producing the same, and more particularly to a rubber compound for coating a surface with a urethane resin layer, a molded product and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a terpolymer type or a copolymer type ethylene propylene rubber (hereinafter simply referred to as EPR) as a useful rubber is excellent in weather resistance and ozone resistance, and thus has many uses. Has been used. On the other hand, a drawback of such EPR is that it is inferior in wear resistance and lubricity, and therefore, in applications where such properties are particularly required, it is necessary to coat the surface of the EPR with a urethane resin or the like for surface modification. there were.

However, since the EPR does not contain an unsaturated bond or a polar group in the main chain, the EPR has poor adhesiveness with a urethane resin or the like. Therefore, conventionally, in order to improve the adhesiveness between the two, a primer (adhesive) is applied between the urethane resin and the EPR, or the diene rubber or the urethane resin is adhesively bonded intermediately to the planned coating site. EPR with
After coating a blend material of a diene rubber, a urethane resin has been coated. Furthermore, various additives have been blended to impart polarity to the EPR.

[0004]

However, all of these methods have problems that the process is complicated, the cost is increased, and the basic characteristics of EPR are significantly impaired. Therefore, it is an object of the present invention to provide an EPR composition capable of forming a urethane resin layer with good adhesiveness. Another object of the present invention is to provide an EPR molded product having a urethane resin formed with good adhesiveness. A further object of the present invention is to provide a method for producing an EPR molded product having a urethane resin layer formed with good adhesiveness.

[0005]

In order to solve the above problems, the present inventors have completed the following inventions. That is, the invention according to claim 1 is a rubber compound of ethylene propylene rubber having the formula:

Embedded image [Wherein X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group], which is a rubber compounded with a silane coupling agent.

Further, in the invention described in claim 2, X is an organic functional group selected from a vinyl group, an epoxy group, a methacrylic group, an amino group and a mercapto group, or a functional group selected from any of these. The rubber compound according to claim 1, which is an organic functional group having a terminal.

The invention according to claim 3 is a rubber compound of ethylene propylene rubber, wherein

[Chemical 6] [Wherein X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group] A rubber containing a white filler surface-treated with a silane coupling agent. It is a compound.

The invention according to claim 4 is the rubber composition according to claim 3, characterized in that silica is compounded in addition to the white filler.

The invention according to claim 5 is based on 100 parts by weight of the ethylene-propylene rubber component of the rubber compound,
The rubber compound according to claim 3, wherein 10 to 100 parts by weight of the white filler is compounded.

According to a sixth aspect of the invention, X is a vinyl group,
The organic functional group of any one of an epoxy group, a methacrylic group, an amino group, and a mercapto group, or an organic functional group having a functional group of any of these at a terminal. It is a rubber compound.

According to a seventh aspect of the present invention, the white filler surface-treated with the silane coupling agent is talc,
The rubber compound according to claim 3, which is at least one kind of clay, calcium carbonate, magnesium carbonate, and alumina.

The invention according to claim 8 is an ethylene-propylene rubber molded product having a urethane resin layer formed on the surface thereof, wherein the rubber molded product is of the formula:

[Chemical 7] [Wherein X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group], or
A urethane resin layer-coated ethylene propylene rubber molded article comprising a white filler surface-treated with this silane coupling agent.

A ninth aspect of the present invention is a method for producing an ethylene propylene rubber molded product having a urethane resin layer formed on the surface thereof, wherein the rubber compound forming the ethylene propylene rubber molded product has the formula:

Embedded image [Wherein X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group], and a silane coupling agent is contained, and this rubber compound is molded to form a molded body. A urethane resin, wherein a urethane resin layer is applied to the surface of the molded body, and the molded body is heated to vulcanize or crosslink to cure the urethane resin layer and adhere to the molded body. A method for producing a layer-coated ethylene-propylene rubber molded body.

The present invention will be described in detail below. The present invention is intended to improve the adhesion between the surface of the molded article of the EPR compound and the urethane resin, and as a means thereof, it is intended to include a silane coupling agent in the EPR compound. Here, EPR is a general term for ethylene propylene rubber and includes EPM and EPDM. EPM is a copolymer of ethylene and propylene, and EPDM is a copolymer of ethylene and propylene and a third component diene monomer (for example, ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene). The EPR compound may contain two or more kinds of copolymer rubber components among these copolymer rubbers.

Since EPR is excellent in weather resistance and ozone resistance, a rubber compound in which only EPR is compounded as a rubber component is preferable, and EPR is ethylene propylene diene 3
A rubber compound containing only the dimensional copolymer as a rubber component is more preferable. The EPR compound is EP
In addition to compounded materials containing only R as a rubber component, these EP
Other rubber components within the range that does not impair the physical properties of R, that is,
Natural rubber (NR), styrene-butadiene copolymer rubber (S
BR), polybutadiene rubber (BR), butyl rubber (IIR) or the like can be blended.

In such EPR blends, various reinforcing agents such as carbon black and calcium carbonate, which are usually used as a compounding agent for rubber, fillers, softeners, various cross-linking agents, cross-linking accelerators, etc. In addition to the additive, a silane coupling agent is added.

Here, the silane coupling agent has the formula

Embedded image [Wherein, X represents an organic functional group and Y represents a monovalent hydrolyzable group], and more specifically, X represents an affinity or reactivity with an organic material such as a urethane resin. Y is a certain organic functional group, and Y is a hydrolyzable group having affinity or reactivity with an inorganic material such as a white filler. Specifically, X can be any organic functional group such as a vinyl group, an epoxy group, a methacryl group, or a mercapto group, or an organic functional group having one of these functional groups at the terminal. Here, the organic functional group having at least one of these functional groups at the end may be an organic functional group such as an alkyl group having at least one of these functional groups at the end, and among them, an amino group or a mercapto group is at the end. The organic functional group contained in is preferable. Examples of Y include an alkoxy group such as a methoxy group and an ethoxy group, a halogen, and the like. As X, one kind or a combination of two or more kinds of organic functional groups may be used. Similarly, as Y, one kind or a combination of two or more kinds of hydrolyzable groups may be used.

Suitable as such a silane coupling agent
Vinyl triethoxysilane CH₂= CH
Si (OC₂H_Five)_Three, Γ-glycidoxypropyltri
Methoxysilane H₂COCHCH₂O (CH₂)_ThreeSi
(OCH_Three)_Three, Γ-methacryloxypropyltrimetho
Xysilane CH₂= C (CH_Three) COO (CH₂)_ThreeS
i (OCH_Three)_Three, Γ-aminopropyltriethoxy
Run H₂N (CH₂) _ThreeSi (OC₂H_Five)_Three, Γ-me
Lucaptopropyltrimethoxysilane HS (CH₂)_Three
Si (OCH_Three)_ThreeCan be mentioned.

The silane coupling agent is prepared by subjecting the white filler compounded in the EPR compound to a surface treatment to obtain EP.
It can also be included in the R formulation. Here, the white filler is an inorganic filler, and examples thereof include talc, clay, calcium carbonate, magnesium carbonate, and alumina. Among them, talc, clay and calcium carbonate are preferable. It should be noted that these white fillers can be used regardless of the particle size, the shape, and the like. Further, these white fillers may be used alone in one rubber compound, or may be used in combination of two or more kinds. It is also possible to mix silica (including hydrous silica) that has not been surface-treated together with a surface-treated white filler. In this case, the blending amount of silica is preferably 20 parts by weight or less with respect to 100 parts by weight of the EPR component. This is because if it exceeds 20 parts by weight, compression set, which is one of the physical properties of vulcanization, deteriorates.

Also in the silane coupling agent used for the surface treatment, X is an organic functional group selected from vinyl group, epoxy group, methacryl group, amino group and mercapto group,
Alternatively, an organic functional group having one of these functional groups at the terminal can be mentioned. Here, the organic functional group having at least one of these functional groups at the end may be an organic functional group such as an alkyl group having at least one of these functional groups at the end, and among them, an amino group or a mercapto group is at the end. The organic functional group contained in is preferable. Examples of Y include an alkoxy group such as a methoxy group and an ethoxy group, a halogen, and the like.

When the white filler surface-treated with the silane coupling agent is added to the rubber compound, it is preferable to add 10 to 100 parts by weight to 100 parts by weight of the EPR component. This is because if the amount of the white filler added is less than 10 parts by weight, the coating film adhesion will be insufficient, and if it exceeds 100 parts by weight, the physical properties of the rubber after vulcanization (particularly the tensile strength and compression set) will be impaired. Further, it is more preferably 30 to 90 parts by weight.

In the surface treatment of the white filler, the white filler and the silane coupling agent are bound to each other by the affinity or reactivity between the hydrolyzable group of the silane coupling agent and the inorganic portion of the white filler. Meanwhile, the organic functional group is in a free state. Therefore, the affinity or reactivity with the urethane resin is maintained. Also,
The silane coupling agent is 0.5 with respect to the white filler.
It is preferably treated in the range of -30%.

The EPR component and other additives can be mixed using a usual rubber kneading method, for example, a Banbury mixer, a two-roll mill or the like. The obtained EPR compound can be molded and vulcanized by a known method such as compression molding, extrusion molding, injection molding and the like.

To form a urethane resin layer on the surface of a molded product of the EPR compound thus blended, a uniformly kneaded rubber compound is molded into a predetermined shape, and the urethane resin is applied to the surface thereof. The molding is performed by vulcanizing or crosslinking (heating) the molded body having the urethane resin applied on the surface.

Vulcanization or crosslinking is performed by heating the molded body at a predetermined temperature for a predetermined time. By this vulcanization or the like, the EPR compound is vulcanized or crosslinked, and by such heating, the X: organic functional group in the silane coupling agent contained in the EPR compound and the isocyanate group of the urethane resin are compatible with each other. It is bound by sex or reactivity. As a result, the urethane resin is firmly adhered to the surface of the rubber compound molded body. In addition, it follows that the shape of the surface of the molded product is adhered to the molded product with good integrity.

As described above, in the present invention, after the EPR compound is molded and before the vulcanization, the urethane resin is applied to the surface of the molded product, and the vulcanization or the crosslinking is followed by heating the urethane resin. Curing and adhesion to the surface of the molded body can be achieved at the same time. Therefore, steps such as the introduction of a primer for bonding the urethane resin can be eliminated, the production process can be simplified and shortened, and the productivity is improved. Further, since the rubber compound contains a material exhibiting adhesiveness with the urethane resin, the adhesiveness with the urethane resin is uniformly exhibited on the surface of the molded body,
The urethane resin is evenly adhered according to the shape of the surface of the molded body. Further, the urethane resin layer is formed with good adhesiveness even on the uneven portion and the complicated portion. That is, according to the present invention, it is convenient when the urethane resin film is formed on the EPR molded body.

Here, the urethane resin means a resin in which the resin is cured by a urethane bond, and examples thereof include a two-component reaction type of a polyol component and an isocyanate component. The coating amount on the surface of the rubber compound molded body is preferably in the range of 20 to 100 μm. 20
If it is less than μm, the lubrication performance is lowered, and if it exceeds 100 μm, the cost merit is lowered. Further, the urethane resin can be applied to the surface of the rubber compound molded product after molding by a known method such as flow coating, brush coating, roller coating, dip coating, spray coating and the like.

As described above, the molded body of the rubber compound coated with the urethane resin layer has a surface layer portion having lubricity on the surface thereof, and the glass run 1 of the vehicle shown in FIG.
For example, it can be widely applied to members whose surface is required to have lubricity. In FIG. 1, 2 is a main body made of EPR, and 3 is a urethane resin layer coated on the main body 2.

[0029]

According to the EPR composition of the present invention,
Since the silane coupling agent is blended, the EPR blend is molded and heated at the time of vulcanization or cross-linking, whereby the silane coupling agent and the urethane resin have an affinity or reactivity with each other, and thus the urethane is formed on the surface of the molded article. Adhesion with resin is exhibited, and urethane resin coating with good adhesion can be easily performed without applying a primer or the like. In addition, according to the EPR mixture containing the white filler surface-treated with the silane coupling agent, the silane coupling agent is mixed with the white filler at the same time,
Mixability and workability can be improved. Further, according to the urethane resin layer-coated EPR molded product of the present invention, the urethane resin is coated by the silane coupling agent contained in the EPR formulation without applying a primer, etc. Since it is firmly adhered to the surface of the molded body, abrasion resistance and lubricity can be reliably imparted to the surface of the molded body, and the urethane resin layer can be maintained against peeling and abrasion. According to the method for producing a urethane resin layer-coated rubber molded article of the present invention, the rubber compound is prepared by blending a silane coupling agent that exhibits adhesiveness with the urethane resin during heating during vulcanization or crosslinking. Sufficient and uniform adhesion of urethane resin to the surface of the rubber compound molded body can be imparted, and curing of the urethane resin and adhesion to the surface of the rubber compound molded body at the same time by heating in the vulcanization or crosslinking process. Done, can improve the production efficiency.

[0030]

Embodiments Embodiments embodying the present invention will be described below. (Examples 1 and 2) In the following examples, according to Table 1, EP
EPR blends (Examples 1 and 2) in which a ternary copolymer type ethylene propylene non-conjugated diene monomer (EPDM), which is one of R, is blended as a rubber component are prepared, and similarly, according to the blending of Table 1, The EPR formulations of Comparative Examples 1-5 were prepared. For these Examples and Comparative Examples, a method commonly used in the rubber industry, that is, a mixer such as an open roll, a Banbury mixer, or a kneader is used to uniformly mix the mixture at room temperature to about 180 ° C. , A rubber compound. The EPDM used in these Examples and Comparative Examples is Esplen 552 manufactured by Sumitomo Chemical Co., Ltd. M.
Nucap 200 manufactured by Huber. Further, talc is a Cyprabond manufactured by Nippon Mistron Co., Ltd.

With respect to Examples 1 and 2 and Comparative Examples 1 to 5 thus prepared, the following items were tested and evaluated. [Adhesion test] A belt-shaped rubber 12 having a thickness of 4 mm and a width of 17 mm extruded at an extrusion temperature of 60 ° C. was extruded from an extruder (D20-15 type manufactured by Toyo Seiki Seisakusho Co., Ltd.) shown in FIG. After spray-coating the urethane resin 14 of 1., it is heated at 200 ° C. for 5 minutes in the vulcanization tank 15 to vulcanize the rubber and the urethane resin layer
8 was formed, and after passing through the pressing roller 16, a rubber molded body 17 having a urethane resin tank 18 was obtained. This rubber molding 1
7 was cut to a length of 80 mm to make a sample, and a cotton cloth 20 was attached to the surface of the urethane resin layer 18 with an instant adhesive 19.
Leave for a day. Then, this sample was cut into a width of 10 mm, and as shown in FIG. 3, the rubber molded body 17 and the cotton cloth 20 were peeled off using an autograph to obtain adhesion strength (adhesion force).
Was measured.

The results of these tests are also shown in Table 1.

[Table 1]

As is clear from the results in Table 1, EPDM
100 parts by weight of aminosilane-treated talc 5
Example 1 with 0 parts by weight and Example 2 with 50 parts by weight of mercaptosilane-treated clay resulted in the base material being destroyed in the adhesion test instead of interfacial peeling,
It was clear that the adhesion between the urethane resin and the surface of the molded product was excellent. On the other hand, in Comparative Examples 1 to 5,
It was clear that interfacial peeling occurred in both cases and that insufficient adhesion was obtained.

(Examples 3 to 7) Next, in the case of varying the amount of clay obtained by subjecting EPDM to mercaptosilane treatment, the rubber compounds (Examples 3 to 7) prepared according to the formulations in Table 2 are taken as examples. I will give you an explanation. As EPDM and other components, the same components as in Examples 1 and 2 were used, kneading was performed in the same manner, and the adhesion test was conducted under the same conditions as in Examples 1 and 2, and the vulcanized physical properties were tested by the following methods. did. In each of the examples, the amount of carbon black blended was varied to adjust the hardness, but there was no effect on the adhesion.

[Vulcanized Physical Properties] Physical properties of vulcanized rubbers are measured by JI
S K6301 Vulcanized rubber was conducted according to the physical test method. 1. Tensile strength (T _B ) A test piece was prepared from each rubber compound into a sheet with a thickness of 2 mm.
It was prepared by vulcanizing at 0 ° C. for 10 minutes and punching out into a No. 3 dumbbell shape. 2. The elongation (E _B ) test piece was the same as the tensile strength. 3. Hardness (H _S ) Rubber compound vulcanized at 180 ° C for 10 minutes, thickness 12m
The hardness was set to m or more and the hardness was measured using a spring type hardness tester A type. 4. Compression set (CS) A test piece specified in JIS K6301 was vulcanized at 180 ° C for 10 minutes, then compressed by 25%, and heat treated at 70 ° C, 2
Two hours.

The test results for Examples 3 to 7 are shown in Table 2.

[Table 2]

As is clear from the results in Table 2, Example 3
The adhesive strength was low and the interfacial peeling occurred. However, in Examples 5 to 7, the base material was destroyed instead of the interfacial peeling due to the high adhesive strength. It was found that the adhesiveness with was excellent. In Example 4, the adhesion was a good value, the interfacial peeling did not occur, and the base material was partially destroyed.
Moreover, the vulcanizates of the standard value (T _B 100kg / cm ² or more, E _B
250% or more, H _s 75 ± 5 degrees, and CS 20% or less), the white filler surface-treated with the silane coupling agent used in this example is 20 parts by weight with respect to 100 parts by weight of EPDM. It is preferable to mix the above,
More preferably, it is 40 parts by weight or more. The upper limit is preferably 80 parts by weight or less.

(Examples 8 to 10) Next, in the compounding of Example 4, the rubber compounding prepared according to Table 3 with respect to the influence on the adhesion and vulcanization physical properties when the hydrous silica (white carbon) was added. (Examples 8 to 10) will be described as an example. As the hydrous silica, Nipseal VN3 manufactured by Nippon Silica was used. As EPDM and other components, the same components as in Examples 1 and 2 were used, kneading was performed in the same manner, and the adhesion test was performed under the same conditions as in Examples 1 and 2, and the same method as in Examples 3 to 7 was used. Were tested for vulcanized physical properties.

The test results for Examples 8-10 are shown in Table 3.
Shown in

[Table 3]

As is clear from the results shown in Table 3, the adhesive strength of all the examples was sufficient, and the base material was destroyed without causing interfacial peeling. On the other hand, the vulcanized physical properties were appropriate values in Examples 8 and 9, but exceeded 20% in Example 10, and it was clear that the compression set decreased as the amount of silica increased. . Therefore, when silica or hydrous silica is used in combination with the white filler surface-treated with the silane coupling agent, considering the compression set, the amount of silica or hydrous silica should be 20 parts by weight or less relative to 100 parts by weight of EPDM. Is preferred.

In the above examples, EPD was used as the rubber component.
Although M is used, the present invention can be similarly applied to a compound containing another EPR as a rubber component. Further, in the above examples, the case where mercaptosilane is used as the silane coupling agent and the white filler is subjected to the surface treatment has been described, but the present invention can be applied to silane coupling agents other than mercaptosilane. The present invention can be applied to the case where the silane coupling agent is added as a simple substance to the composition.

[Brief description of drawings]

FIG. 1 is a view showing one embodiment of a rubber molded body coated with a urethane resin layer of the present invention.

FIG. 2 is a view showing an apparatus for carrying out a rubber compound extrusion step and a vulcanization step in an example of the present invention.

FIG. 3 is a diagram showing a method for measuring the adhesive force of a urethane resin layer coated on the surface of a rubber molded body in an example of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08K 5/54 C08K 5/54 9/06 KFU 9/06 KFU

Claims (9)

[Claims] 1. A rubber compound of ethylene propylene rubber having the formula: A rubber compound comprising a silane coupling agent represented by the formula [wherein X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group]. 2. X is an organic functional group selected from the group consisting of vinyl group, epoxy group, methacrylic group, amino group and mercapto group, or an organic functional group having any of these functional groups at the end. The rubber compound according to claim 1, which is characterized in that. 3. A rubber blend of ethylene propylene rubber having the formula: [Wherein X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group] A rubber containing a white filler surface-treated with a silane coupling agent. Compound. 4. The rubber compound according to claim 3, wherein silica is compounded in addition to the white filler. 5. The white filler is added to 10 parts by weight of 100 parts by weight of an ethylene propylene rubber component of the rubber compound.
The rubber compound according to claim 3, which is compounded in an amount of 100 parts by weight. 6. X is an organic functional group selected from a vinyl group, an epoxy group, a methacrylic group, an amino group and a mercapto group, or an organic functional group having a functional group selected from these groups at the end. The rubber compound according to claim 3, characterized in that 7. The white filler surface-treated with the silane coupling agent is talc, clay, calcium carbonate,
The rubber compound according to claim 3, which is at least one of magnesium carbonate and alumina. 8. An ethylene propylene rubber molded body having a urethane resin layer formed on the surface thereof, wherein the rubber molded body is represented by the formula: [Wherein X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group], or
A urethane resin layer-coated ethylene propylene rubber molded article comprising a white filler surface-treated with this silane coupling agent. 9. A method for producing an ethylene propylene rubber molded product having a urethane resin layer formed on the surface thereof, wherein the rubber compound forming the ethylene propylene rubber molded product has the formula: [Wherein, X represents a monovalent organic functional group and Y represents a monovalent hydrolyzable group], and a silane coupling agent is contained. The urethane resin is characterized in that a urethane resin layer is applied to the surface of the molded body, and the molded body is heated to vulcanize or crosslink to cure the urethane resin layer and adhere to the molded body. Method for producing layer-coated ethylene propylene rubber molding.