JPH01236242A - Production of polyacetal for forming composite with elastomer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a new method for producing modified polyacetals for elastomer composites. More specifically, the present invention relates to a method for producing polyacetal for elastomer composites in which the adhesion to elastomers is significantly improved by subjecting polyacetal having a high elastic modulus to a special surface treatment.

Conventional technologyPolyacetal has high tensile strength and excellent fatigue resistance and water repellency, so it is widely used in various fields as engineering plastics and as a material for synthetic fibers. Improvements have progressed, and as a result of the development of products with high elastic modulus and high strength, it has started to attract attention as a material for elastomer composites.

However, when this polyacetal is combined with an elastomer, it has the disadvantage that it is difficult to obtain sufficient adhesion due to lack of affinity.

Therefore, in order to improve these defects, the surface of the polyacecooled material is mechanically roughened using sandpaper or sandblasting, physically etched using corona discharge, or treated with potassium dichromate or phosphorus. Chemical etching with acids, fluorine, etc. is used, but although these methods improve adhesion based on physical effects such as anchoring, they do not improve the inherent adhesion such as chemical bonding. Therefore, satisfactory results are not necessarily obtained in terms of permanent adhesion, peeling resistance, and adhesion against dynamic fatigue.

On the other hand, aged products of resorcinol-formaldehyde-rubber latex, so-called RFL, and resol, an initial condensation product of resorcinol and formaldehyde, etc.
Although these are well known as adhesives for fiber cords for reinforcing elastomers, they are not effective at all in improving the adhesive strength of polyacetal.

The reason why polyacetal lacks affinity with elastomers is that, unlike highly polar materials such as nylon and cellulose, it does not have functional groups on its surface. By orienting it, it becomes larger and larger.

Problems to be Solved by the Invention The present invention solves the problem by modifying the surface of high modulus polyacetal.
The purpose of this invention is to provide a high modulus polyacetal that exhibits permanent adhesion, excellent peeling resistance, and heat deterioration resistance when combined with an elastomer.

Means for Solving the Problems The present inventors have conducted intensive research to develop a polyacetal that has good adhesion to elastomers. It was discovered that the above object could be achieved by treatment with a specific drug, and based on this knowledge, the present invention was completed.

That is, in the present invention, a mixture of a phenolic compound and a resorcinol-formaldehyde condensate, or a mixture of a phenol compound and a matured resorcinol-formaldehyde latex product is attached to the surface of a polyacetal having a tensile modulus of 4GF1 or more, and then The present invention provides a method for producing polyacetal for elastomer composites, which is characterized in that after heat treatment, an adhesive for elastomers is further applied thereon as required.

The present invention will be explained in detail below.

The polyacetal used in the method of the present invention may be either a homopolymer or a copolymer. As the homopolymer, a number average molecular weight I5,000 to 200,000 (M
IO, 1-50), preferably 25,000-100
,000 (M I 0.5 to 30). On the other hand, as a copolymer, a polyoxymethylene copolymer having one or more types of ether segments or polyether segments in the molecular chain, and at least a cyclic ether and at least one type of alkylene oxide are copolymerized. with an average molecular weight of 10,000 to 200.000 (MI 0.1 to
50), preferably 20. Goo~100, Goo (
A copolymer having an M I in the range of 0.5 to 30) is used. Such a copolymer may contain, for example, 90 to 99.6 mol% of oxymethylene units, preferably 95 to 9 mol% of oxymethylene units.
9.6 mol %, and 0.4 to 10 mol % of ether segments having 2 or more carbon atoms are interspersed in the molecular chain. If the content of this oxymethylene unit is less than 90 mol %, the strength and elastic modulus are undesirably low, and if it exceeds 99.6 mol %, the strength and elastic modulus are substantially the same as those of a homopolymer. The polyacetal used in the present invention is one whose molecules are oriented in at least one axis. This product is obtained by molecularly orienting unoriented polyacetal, which is normally obtained by melt extrusion, by a method such as stretching, rolling, or isostatic extrusion.

In the present invention, as this polyacetal oriented body,
Tensile modulus is 4 GPa or more, preferably 10 GPa or more, more preferably 20 GPi or more, particularly preferably 3
A material having a high elastic modulus of 0 GPa or more is used. Moreover, the tensile strength of this oriented body is usually 0.6GF1 or more, but it is 1.0GP! As mentioned above, those having a strength of preferably 1.3 GPa or more, particularly preferably 1.5 GPa or more are advantageously used in terms of high strength.

In the present invention, polyacetals formed into arbitrary shapes, such as films, sheets, fibers, blocks, tubes, rods, spheres, pellets, chips, and powders, can be used.

In the method of the present invention, the phenolic compound used to modify the surface of the polyacetal has at least one aromatic ring and at least one aromatic ring bonded to the aromatic ring.
It is an aromatic compound having hydroxyl groups, and in addition to hydroxyl groups, for example, alkyl groups, halogenated alkyl groups, oxyalkyl groups, aminoalkyl groups, alkenyl groups, alkynyl groups, aryl groups, halogen atoms, formyl groups,
carboxyl group, carbonyl group, ether group, epoxy group, amino group, imino group, cyano group, cyanoacrylic group, acrylic group, nitro group, sulfone group, mercapto group,
It may have a substituent such as a triazine group. Examples of such phenolic compounds include phenol, resorcinol, catechohydroquinone, pyrogallol, 70glucine, aminophenol, dihydroxyaniline, cyanophenol, nitrophenol,
Picric acid, Fresi-4, xylenol, carvacrol, thymol, naphthol, resorcyl aldehyde, resorcyl hydroquinone, salicylic acid, ? : )' t1
7 + Cybenzoic acid, hydroxyphenylacetic acid, protocatechuic acid, geltisylic acid, resorcinic acid, orceric acid, caffeic acid, lamberic acid, gallic acid, 3-hydroxyphthalic acid, bisphenol A, x, x-bis(4- Hydroxybenzyl alcohols such as hydroxyphenyl) hexafluoropropane, chlorophenol, bromophenol, halogenated phenols such as polyvalent halogenated phenol, monohydroxybenzyl alcohol, trihydroxybenzyl alcohol, etc. . Among these, in particular, trihydroxybenzenes such as resorcinol, catechol, hydroquinone, and pyrogallol, aminophenols such as floramine, m-aminophenol, hydroxyaniline,
Preferred are halogenated phenols such as chlorophenol and hydroxybenzyl alcohols. this.

These phenols may be used alone, or
You may use two or more types in combination.

In the present invention, a mixture of the above-mentioned phenolic compound and a resorcinol-formaldehyde condensed metal product or a resorcinol-formaldehyde-latex aged product is used as the treatment liquid. By using such a treatment liquid, adhesion is dramatically improved and heat deterioration resistance and the like are improved compared to when only a phenolic compound is used.

The resorcinol-formaldehyde condensate is usually R
Let's call it F, resorcinol and pormaldehyde.
It is obtained by reacting in the absence of a catalyst or in the presence of an acid catalyst or an alkali catalyst.

In this reaction, formaldehyde is usually used in an amount of 2 moles or less per 1 mole of resorcinol.

On the other hand, a resorcinol formaldehyde latex aged product is usually called RFL, and is obtained by adding latex to the above-mentioned RF and aging it. Examples of the latex include natural rubber latex, styrene-butadiene rubber latex, vinylpyridine terpolymer latex, nitrile rubber latex, silicone rubber latex, urethane rubber latex, polyvinyl chloride latex, polyvinylidene chloride latex, etc. alone or in combination. A combination of the above is used. When polyacetal is combined with vulcanized rubber, latexes such as natural rubber, styrene-butadiene rubber, vinylpyridine terpolymer, and nitrile rubber are preferably used.

The concentration of phenolic compounds in the treatment solution is usually 1
The concentration is selected in the range from 0% by weight or more, preferably 20% by weight or more, more preferably 30% by weight or more to saturated concentration. In addition, phenolic compounds in the treatment liquid and the RF
The proportion of RF varies depending on the type of elastomer to be composited. For example, when the elastomer is vulcanized rubber, the solid content is usually 0.01 to 2 parts by weight of RF per 1 part by weight of the phenolic compound. Used in percentages.

If the amount of RF is less than 0.01 parts by weight, the effects of the present invention will not be fully exhibited, and if it exceeds 2 parts by weight, adverse effects may occur. Regarding the ratio of the phenol compound to the RFL, the RFL is usually used in a ratio of 0.02 to 0.2 parts by weight per 1 part by weight of the phenol compound. If the amount of RFL is less than 0.02 parts by weight, the effects of the present invention will not be fully exhibited;
If it exceeds 2 parts by weight, it may have an adverse effect.

In order to attach the treatment liquid consisting of the above-mentioned mixture to the polyacetal surface, for example, a method of immersing the polyacetal in the treatment liquid, a method of applying the treatment liquid to the polyacetal surface, a method of spraying, etc. are used. At this time, the surface of the polyacetal can be mechanically roughened by sandblasting or the like to improve the wettability of the treatment liquid.

In this way, by heat-treating the polyacetal to which the mixture has been adhered to the surface, a resin layer that is tightly adhered to the polyacetal surface and has a high affinity for the elastomer adhesive is formed. This is because when the phenol compound contains RF or RFL, the phenol compound reacts with the polyacetal, forming a type of phenol resin layer chemically bonded to the surface of the polyacetal. This is thought to be because RF or RFL present in the phenolic resin layer increases the freshness of the elastomer adhesive.

The heat treatment is carried out at a temperature that is higher than the melting temperature of the phenolic compound and lower than the softening temperature of the polyacetal. The conditions for this heat treatment are appropriately selected depending on the type of polyacetal and phenol compound used, but usually at a temperature in the range of 100 to 180°C,
Heat treatment is performed for about seconds to 10 minutes. When using resorcinol as the phenolic compound, the heat treatment is performed at a temperature in the range of 150 to 170°C for 10 to 10 minutes.
It is preferable to do this for about 30 seconds.

When a phenolic compound with a low melting point is used, no particular solvent is required.

Furthermore, the treatment can be accelerated by using an acid, alkali, peroxide, etc. as a catalyst. In addition, for example, ammonia, amines, polyamines, alcohols, epoxy compounds, acrylic compounds, incyanate compounds, carbamic acid derivatives, sulfur compounds, peroxides, crosslinking agents, etc. can be used in combination to form a resin layer and copolymerize. , crosslinking, etc. can also be performed.

In the present invention, an adhesive layer for elastomer may be provided on the surface treated layer of polyacecool formed in this way, if necessary. This elastomer adhesive is appropriately selected depending on the type of elastomer used.

There are no particular restrictions on the elastomer, and any elastomer can be selected from those conventionally used. Examples of the elastomer include natural rubber, 5BRS IR, BRSEPR, butyl rubber, polyisobutylene, chloroprene rubber, neoprene rubber, NB
R, polyurethane rubber, polysulfide rubber, halogenated rubber, polybutadiene rubber, polyethylene propylene rubber,
Examples include, but are not limited to, acrylic rubber, chlorohydrin rubber, fluorine rubber, silicone rubber, various synthetic resin elastomers, and compositions thereof.

As the adhesive for the elastomer, for example, when cross-sulfurized rubber is used as the elastomer, RFL is usually used, when polyvinyl chloride is used, polyvinyl chloride latex is used, and when polyvinylidene chloride is used, polyvinyl chloride latex is used. When polyurethane is used as vinylidene chloride latex, polyurethane rubber latex is preferably used. Furthermore, in addition to the above-mentioned adhesives for elastomers, urea-based, melamine-based, isocyanate-based, phenol-based, polyamide-based, urethane-based, cyanoacrylate-based, acrylic-based, polyester-based, nitrocellulose-based,
Vinyl acetate resins, epoxy resins, vinyl acetals, vinyl alcohols, and modified products thereof can also be used.

In addition, the polyacetal used in the present invention includes:
For the purpose of improving its chemical inertness, various elastomers such as polyamide elastomer, polyester elastomer, polyurethane elastomer, glass fiber, carbon black, polyurea, polythiourea, phenolic resin, urea resin, etc. can be blended. can. Furthermore, as necessary, additives such as antioxidants, heat stabilizers, flame retardants, oil agents, lubricants, plasticizers, antistatic agents, colorants, and softeners, and various fillers such as carbon fiber, Whiskers, synthetic fibers, ceramics, etc. can also be added to impart the desired properties.

Next, the method of the present invention will be explained according to the attached drawings.
The figure is a block diagram of an example of a manufacturing process suitable for continuously implementing the method of the present invention, in which the oriented polyacetal material A enters the roughening section 2 from the feeding roll 1, and is mechanically The surface is roughened, and then a mixture of a phenolic compound and RF or RFL is applied in the active part 3, and heat treated in the heat treatment part 4, and then passed through the adhesive application part 5 for elastomer and the heat treatment part 6. , an adhesive layer is provided, and the winding roll 7
It is wound up.

Further, other processing units such as a take-off machine, an annealing device, and a cooling device can be incorporated into this process as necessary. The heat treatment can be performed using a conventionally used method, such as an external heating method using steam or an electric heater, or an internal heating method using electromagnetic waves such as high frequency, infrared rays, far infrared rays, or laser.

Effects of the Invention According to the method of the present invention, a high modulus polyacetal for use in elastomer composites with significantly improved adhesion can be produced by subjecting the high modulus polyacetal to a special surface treatment. When combined with an elastomer using this polyacetal, it has permanent adhesion, peeling resistance,
An elastomer-polyacetal composite with excellent adhesion against dynamic fatigue, heat deterioration resistance, etc. can be obtained.

The polyacetal for elastomer composites obtained by the method of the present invention can be used in the fields of elastomer reinforcements, such as tire cords, bead wires, belts, hoses, pipes, sheets, etc.
Widely used for core bodies such as diaphragm valves and sail chains, ropes coated with elastomers and resins, cable tension members, fishing nets, nets, tents, canvases, filter cloths, heavy cloths, canvases, rolls, bearings, etc. can do. In addition, it can be applied to composites with plastics, concrete, paper, ceramics, metals, wood, leather, glass, etc., as well as to plating, printing, painting, etc.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, in the following examples, stretched bodies of polyacecool were prepared according to the method described in JP-A-60-18310. Mat:, each physical property was determined as follows.

(1) Tensile modulus and tensile strength Measured using an Instron tensile tester according to JIS K 71N (+981). The tensile modulus was measured using a differential transformer strain meter method, and the tensile strength was measured by winding the sample several times around a grooved stainless steel reel jig with a tensile strength of 160 d at a distance between the reels of 20 cm and a tensile speed of 10 crm/sin. Further, the cross-sectional area necessary for calculating the tensile modulus and tensile strength was calculated from the weight of a sample of a certain length and the apparent density determined by the following method.

(2) Apparent Density The apparent density was measured by the float-sink method of JIS K 7112 (1980) using an aqueous solution of anhydrous potassium carbonate as a density medium at a temperature of 20±O, S'0.

(3) Adhesive strength JIS L 101? (103) A method (T test)
I followed the instructions. That is, the length of the elastomer that composes one end of the surface-modified polyacetal linear body B with a length of 210 + nm, the length of the elastomer, the width of 201 + II + 1 and the height of 10 m.
A sample having the shape shown in Fig. 2 was created by embedding it in the upper center of a cube C of m, to a depth of 101 + lff1, and the stress when pulling out the polyacetal from the elastomer piece was measured.
Adhesive strength was determined from the following formula.

Preparation Example I Preparation of RF liquid 16.2 parts by weight of resorcinol, 37% by weight of formalin 2
0.0 parts by weight, 0.41 parts by weight of sodium hydroxide, 3 parts by weight of water
It was prepared by mixing 73.8 parts by weight and stirring at 23°C for 16 hours.

Preparation Example 2 Preparation of RFL liquid 16.2 parts by weight of resorcinol, 37% by weight of formalin 2
0.0 parts by weight, 0.41 parts by weight of sodium hydroxide, 3 parts by weight of water
73.8 parts by weight were mixed and stirred at 23° C. for 6 hours to obtain a solution containing 2 parts by weight of vinyl pyridine terpolymer latex (solid content 40% by weight) [manufactured by Jusumi Noga Tatsuta Co., Ltd., trade name Viratex] H2. SBR latex (solid content 32% by weight) [manufactured by Nippon Zeon Co., Ltd., product name J-9049
] 43.3 parts by weight and 8 parts by weight of NR latex (solid content 60% by weight) manufactured by EHMPB, trade name H&C 111, were added, and after stirring at 23°C for 24 hours, 18.0 parts by weight of 28% ammonia water was added. of the latex was added, and the concentration was further adjusted so that the solid content of the total latex was 40% by weight, thereby preparing an RFL liquid.

Examples 1 to 7, Comparative Examples 1 and 2 Outer diameter 2,4 ram/inner diameter 0 obtained by melt extruding pellets of Tenac 3010 [manufactured by Asahi Kasei Industries, Ltd., registered trademark of acetal homopolymer] at 200°C .8mm
The tube was continuously stretched under pressure to obtain an oriented polyacetal as shown in Table 1. The oriented body is 12
Using No. 0 alumina, sandblast and add 30 parts by weight to a mixed solution of 40 parts by weight of resorcinol and 60 parts by weight of RF liquid.
After immersing it for seconds, it was taken out and dried at 160°C for 20 seconds, then immersed in RFL liquid at 23°C for 30 seconds, then taken out, dried at 120°C for 5 minutes, and then heated at 165°C for 5 minutes. Dry heat treatment was performed for 1 minute. This was combined with carcass compound rubber for automobile tires, and heated to 35 ky/c at a temperature of 150°C and a press pressure of 35 ky/c.
Heat treated for 0 minutes to create a sample as shown in Figure 2.
The oriented polyacetal body was pulled out from the rubber piece, and the adhesive strength was determined. The results are shown in Table 1. For comparison, results obtained in the same manner as above using a 40% by weight aqueous resorcinol solution, RF liquid, and RFL liquid as modifiers are also shown.

In addition, in Examples 1 to 7, a large amount of rubber adhered to the sample after drawing. Further, as a result of conducting a heat resistance deterioration test for 121'0.24 hours (7) on the rubber-bonded sample of Example 5, the retention rate of the pull-out strength was 80%.
.

Examples 8 to 14, Comparative Example 3 The same stretched body as in Examples 1 to 7 was sandblasted using No. 120 alumina, and a mixed solution of 40 parts by weight of Resolzial, 20 parts by weight of RFL liquid, and 40 parts by weight of water was prepared. To,
After immersing it for 30 seconds, it was taken out, and after dry heat treatment at 160°C for 20 seconds, it was immersed in RFL liquid at 23°C for 30 seconds, then taken out, dried at 120°C for 5 minutes, and then heated at 160°C. A dry heat treatment was performed for 5 minutes. Rubber was bonded in the same manner as in Examples 1 to 7 to prepare samples, and the bond strength was determined. The results are shown in Table 2. For comparison, the results of the same procedure as above using only the RFL liquid as the modifier are also listed.

In addition, in Examples 8 to 13, a large amount of rubber adhered to the sample after drawing. Further, as a result of conducting a heat resistance deterioration test at 121° C. for 24 hours on the rubber-bonded sample of Example 12, the retention rate of the drawing strength was 80%.

Examples 15 to 19 The same procedure as in Example 5 was carried out, except that the same stretched body as in Example S was used and a mixed solution of resorcinol and RF liquid having the composition shown in Table 3 was used as the modifier. A sample was prepared and the adhesive strength was determined.

The results are shown in Table 3.

Examples 20 to 23 Using the same stretched body as in Example 12, using a mixed solution of resorcinol and RFL liquid having the composition shown in Table 4 as a modifier, and using the same procedure as in Example 12 except for t: go,
A sample was prepared and the adhesive strength was determined. The results are shown in Table 4.

Examples 24 to 25, Comparative Examples 4 and 5 Using the same stretched body as in Example 5, it was sandblasted using No. 120 alumina, and then mixed with a mixture of various 7 enols and RF liquid for 30 minutes. The sample was immersed for seconds, taken out, and subjected to dry heat treatment at 160°C for 20 seconds, followed by RFL treatment and rubber adhesion in the same manner as in Example 5 to prepare a sample and determine the adhesive strength. . The results are shown in Table 5. For comparison purposes, the results obtained using phenols alone as the modifier in the same manner as above are also shown.

Examples 26 to 28 Duracon Mis-04 [manufactured by Polyplastics Co., Ltd.]
19 pellets of registered trademark name of acetal copolymer]
A tube having an outer diameter of 2.4 rtna/inner diameter of 0.8 m+m obtained by melt extrusion at 0° C. was continuously stretched under pressure to obtain a stretched polyacetal body. The stretched body was subjected to N.

After sandblasting using No. 2 alumina, it was immersed for 30 seconds in a mixed solution consisting of 40 parts by weight of resorcinol, a modifier, and 60 parts by weight of RF liquid, and then taken out and subjected to dry heat treatment at 160°C for 20 seconds. Thereafter, in the same manner as in Examples 1 to 7, RFL treatment and rubber adhesion were performed in this order to prepare samples, and the adhesive strength was determined. The results are shown in Table 6.

Example 2911 Tenac 3010 pellets were fed into an extruder at 200°C.
1, extruded through a spindle with 0.60mm-
A multifilament having +u+
, tensile modulus 140 GPi, tensile strength 1.7 G
A drawn yarn with Pa and elongation of 6 to 8% was obtained.

The drawn yarn is processed using a device as shown in FIG. 5.
Processing was carried out continuously. However, the surface was not roughened. As a modifier, 40 parts by weight of resorcinol and R
A mixed solution consisting of 60 parts by weight of liquid F was used, the residence time in the active section 3 was 16 seconds, the temperature in the heating section 4 was 160° C., and the residence time was 202 seconds. RF tL liquid was used as the adhesive for the elastomer, the residence time l in the adhesive adhesion section 6 was 16 seconds, the temperature in the heat treatment section 6 was 180° C., and the residence time was 1 minute. The elastic modulus, strength, and adhesive strength of the modified polyacetal drawn yarn obtained by winding were measured. As a result, the elastic modulus was 34 GPi, 1.6 GF!, and the adhesive strength was 4 Gg/mm.

For comparison, nylon-66 tire cord 2HOd (2 strands of single yarn 6d and 1160d, wire diameter),
(equivalent to 56mm) was treated with RFL liquid according to the usual method and bonded to rubber to determine the adhesive strength, which was 970g/i++i''?
there were. Thus, according to the present invention, polyvital can be brought into tighter contact with the elastane 7- than the conventional tire cord.

Example 30 The same stretched body as in Example 5 was subjected to No. 120 sandblasting treatment, and 40 parts by weight of resorcinol and 4 parts by weight of resorcinol were added as modifiers.
．． Using a mixed solution consisting of 5 parts by weight of 4'-methylene-bis(2-chloroaniline) and 55 parts by weight of RF THF solution, the mixture was immersed for 30 seconds. A dry shade treatment was performed for 20 seconds.

Next, this was placed in a mold, and 90 parts by weight of Adiprene L-Zoo [manufactured by Uniroyal Chemical Co., Ltd.], which is a polyurethane thread misalignment polymer, and 10 parts by weight of 64.4'-methylenebis(2-chloroaniline) as a curing agent were added. 100 of
A mixed solution of 'C was poured and cured by heat treatment at 100° C. for 60 minutes to prepare a sample as shown in FIG. 2, and the adhesive strength was measured.

As a result, the pullout strength was 10&91, and the adhesive strength was 640.
97 mm''. Furthermore, polyurethane was attached to the sample after being pulled out.

[Brief explanation of the drawing]

FIG. 1 is a brochure diagram showing an example of the manufacturing process for carrying out the method of the present invention, in which symbol A is polyacetal, 1 is a feeding roll, 2 is a roughened part, 3 is an active part, 4 5 is a heat treatment section, 5 is an elastomer adhesive application section, 6 is a heat treatment section, and 7 is a take-up roll. FIG. 2 is a perspective view of a sample prepared for measuring the adhesive strength between polyacetal and elastomer, in which reference numeral B indicates modified polyacetal and C indicates elastomer. Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Scope of Claims] 1. A mixture of a phenolic compound and a resorcinol-formaldehyde condensate, or a mixture of a phenol compound and a matured resorcinol-formaldehyde latex product is attached to the surface of a polyacetal having a tensile modulus of 4 GPa or more, A method for producing polyacetal for elastomer composites, the method comprising subsequently performing heat treatment. 2. A mixture of a phenolic compound and a resorcinol-formaldehyde condensate, or a mixture of a phenol compound and a matured resorcinol-formaldehyde latex product is attached to the surface of a polyacetal having a tensile modulus of 4 GPa or more, and then heat-treated. A method for producing polyacetal for elastomer composites, which further comprises adhering an adhesive for elastomers thereon.