JP6931321B2 - Adhesive resin composition and composite molded product - Google Patents

Description

The present invention relates to adhesive resin compositions and composite moldings. In particular, the present invention relates to an adhesive resin composition for joining a polyacetal resin molded body containing a polyacetal resin and a polyethylene resin molded body containing a polyethylene resin.

Polyacetal resin, which is an engineering plastic, has excellent mechanical properties, electrical properties, slidability, and chemical resistance, and is therefore widely used in, for example, automobile parts, electrical / electronic equipment parts, and OA parts. Among these, as an application that makes the best use of the excellent chemical resistance of polyacetal resin, there are fuel tank connecting parts such as flanges, valves, tubes, etc. that are connected to the fuel tank of automobiles, which are in direct contact with fuel such as gasoline. Be done.

On the other hand, in recent years, polyethylene resin has been used as a material for fuel tanks of automobiles for the purpose of reducing the weight of the vehicle body and improving fuel efficiency.

Here, as a method of attaching the above-mentioned polyacetal resin fuel tank connecting component to the fuel tank using the polyethylene resin, for example, a method of welding the polyacetal resin and the polyethylene resin is known. However, the weldability of the interface between the polyacetal resin and the polyethylene resin is usually low, and there is a problem that the welded portion is easily peeled off by an external force and the volatile fuel leaks from the interface between the resins. In particular, fuels are highly volatile and can cause air pollution, so such fuel leaks are being regulated worldwide. Therefore, there has been a strong demand for the development of a composite molded product in which a polyacetal resin and a polyethylene resin are integrated.

As an example of such a composite molded body, the following structure is described in Patent Document 1 below.
The thermoplastic resin bonded structure composed of two or more kinds of resin components is characterized by having at least one structure in which the two adjacent components are the component (A) and the component (B) shown below. Thermoplastic resin bonded structure.
Component (A); 5 to 80% by mass of polyacetal resin (hereinafter referred to as component (A-1)) with respect to the total mass of component (A) and 20 to 95 mass with respect to the total mass of component (A). A resin composition comprising one or more resin compositions (hereinafter referred to as (A-2) component) selected from% polyolefin resin, olefin-based elastomer, or hydrogenated butadiene-based elastomer.
Component (B); Thermoplastic resin

Further, in Patent Document 2 below, a polyacetal resin molded body containing a polyacetal resin (A1), a polyethylene resin molded body containing a polyethylene resin (B3), and the polyacetal resin molded body and the polyethylene resin molded body are provided. A composite molded body having an intermediate layer to be formed, wherein the intermediate layer contains a polyacetal resin (A2) and a polyethylene resin (B2), and only the intermediate layer, only the polyacetal resin molded body, and the polyacetal resin molded body. And only the intermediate layer, only the polyacetal resin molded body and the polyethylene resin molded body, or all of the polyacetal resin molded body, the polyethylene resin molded body and the intermediate layer contain the inorganic filler (C), and the polyacetal Among the resin molded body, the intermediate layer, and the polyethylene resin molded body, the content of the inorganic filler (C) in the resin molded body containing the inorganic filler (C) or the intermediate layer is larger than 1% by mass, respectively. Moreover, a composite molded body having a weight of less than 40% by mass is disclosed.

Japanese Unexamined Patent Publication No. 2002-138185 JP-A-2017-80939

Here, the intermediate layer (adhesive layer) described in Patent Document 2 may contain a stabilizer. Polyamide resins, specifically nylon 6 and nylon 66, are known as examples of stabilizers. However, since nylon 6 and nylon 66 do not melt at the general processing temperature of the polyacetal resin, there is a problem that the processability is inferior. It is also possible to raise the processing temperature of the polyacetal resin, but there is concern about the problem of mold deposit. On the other hand, it is conceivable to use a polyamide resin having a low melting point such as nylon 12, but there is a problem that it turns black during processing and becomes a black spot foreign substance.
An object of the present invention is to solve the above problems, an adhesive resin composition in which mold deposits are suppressed and black spot foreign substances are suppressed while ensuring a certain level of adhesiveness, and the adhesive. An object of the present invention is to provide a composite molded product using a sex resin composition.

As a result of diligent studies by the present inventor based on the above problems, in an adhesive resin composition containing a polyacetal resin and a polyethylene resin, a polyamide dimerate having a melting point of 180 ° C. or less is used as a stabilizer, and the adhesive resin composition is used. It has been found that the above-mentioned problems can be solved by setting the blending amount within a predetermined range.
Specifically, the above problems were solved by the following means <1>, preferably by <2> to <7>.
<1> A polyacetal resin, a polyethylene resin, and a polyamide dimerate having a melting point of 180 ° C. or lower are contained, and the content of the polyamide dimerate is 0.1 to 2 of the total content of the polyacetal resin and the polyethylene resin. An adhesive resin composition which is 0% by mass and has a mass ratio of the polyacetal resin to the polyethylene resin of 10 to 70: 90 to 30.
<2> The adhesiveness according to <1>, wherein the polyethylene resin contains an acid-modified polyethylene resin, and the acid modification rate of the acid-modified polyethylene resin is 0.01% by mass or more of the total mass of the acid-modified polyethylene resin. Resin composition.
<3> The adhesive resin composition according to <1> or <2>, wherein the acid-modified polyethylene resin is a maleic anhydride graft-modified polyethylene resin.
<4> The adhesive resin according to any one of <1> to <3>, wherein the melt flow rate of the polyacetal resin measured under the conditions of 190 ° C. and 2.16 kg load is 30 g / 10 minutes or less. Composition.
<5> Adhesive resin to any one of <1> to <3> in which the melt flow rate of the polyethylene resin measured under the conditions of 190 ° C. and 2.16 kg load is 2.5 g / 10 minutes or less. Composition.
<6> The adhesive resin composition according to any one of <1> to <5>, wherein the density of the polyethylene resin is 0.965 g / cm ^{3 or less.}
<7> A polyacetal resin molded body containing a polyacetal resin, a polyethylene resin molded body containing a polyethylene resin, and the polyacetal resin molded body and the polyethylene resin molded body are provided between the polyacetal resin molded body and the polyethylene resin molded body. A composite molded body having a body and intermediate layers in contact with each other, wherein the intermediate layer is formed from the adhesive resin composition according to any one of <1> to <6>.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an adhesive resin composition in which mold deposit is suppressed and black spot foreign matter is suppressed while ensuring a certain degree of adhesiveness, and a composite molded product using the adhesive resin composition. Became.

It is sectional drawing which shows one Embodiment of the composite molded article of this invention.

Hereinafter, the contents of the present invention will be described in detail. In addition, in this specification, "~" is used in the meaning that the numerical values described before and after it are included as the lower limit value and the upper limit value.

The adhesive resin composition of the present invention contains a polyacetal resin, a polyethylene resin, and a polyamide dimerate having a melting point of 180 ° C. or lower, and the content of the polyamide dimerate is the total content of the polyacetal resin and the polyethylene resin. It is 0.1 to 2.0% by mass, and the mass ratio of the polyacetal resin and the polyethylene resin is 10 to 70: 90 to 30. With such a configuration, it is possible to provide an adhesive resin composition in which mold deposits are suppressed and black spot foreign substances are suppressed while ensuring a certain level of adhesiveness. Furthermore, the amount of formaldehyde generated can be suppressed.

<Polyacetal resin>
The adhesive resin composition of the present invention contains a polyacetal resin. Even if the polyacetal resin contained in the adhesive resin composition is a homopolymer containing only a divalent oxymethylene group as a constituent unit, it contains a divalent oxymethylene group and a divalent oxyethylene group as constituent units. Although it may be a copolymer, it is preferably a copolymer containing a divalent oxymethylene group and a divalent oxyethylene group as constituent units. When the polyacetal resin is a copolymer containing a divalent oxymethylene group and a divalent oxyethylene group as constituent units, the composite molded product is also excellent in thermal stability because it is excellent in thermal stability.

When the polyacetal resin is a copolymer containing a divalent oxymethylene group and a divalent oxyethylene group as constituent units, the ratio of the oxyethylene group to 100 mol of the oxymethylene group (amount of comonomer) is particularly limited in the polyacetal resin. However, it is preferably 1.0 mol or more. In this case, the intermediate layer may have better adhesiveness to the polyethylene resin molded product as compared with the case where the oxyethylene group is contained in a ratio of less than 1.0 mol with respect to 100 mol of the oxymethylene group. This makes it possible to more sufficiently suppress peeling between the polyacetal resin molded product and the intermediate layer. The ratio of the oxyethylene group to 100 mol of the oxymethylene group is more preferably 1.2 mol or more, and particularly preferably 1.4 mol or more. The ratio of the oxyethylene group to 100 mol of the oxymethylene group is preferably 5.5 mol or less, more preferably 4.0 mol or less, and may be 3.0 mol or less.

In order to produce the polyacetal resin, trioxane is usually used as a main raw material. Further, in order to introduce an oxyethylene group into the polyacetal resin, for example, 1,3-dioxolane or ethylene oxide may be used as a comonomer.

The melt flow rate (MFR) measured under the condition of 190 ° C. and 2.16 kg load of the polyacetal resin is not particularly limited, but is preferably 60 g / 10 minutes or less, and is preferably 50 g / 10 minutes or less. More preferably, it is more preferably 30 g / 10 minutes or less, further preferably 20 g / 10 minutes or less, further preferably 10 g / 10 minutes or less, and 5.0 g / 10 minutes or less. It is even more preferable that the amount is 3.0 g / 10 minutes or less. By setting the melt flow rate to 60 g / 10 minutes or less, the intermediate layer has better adhesiveness to the polyacetal resin molded product, so that the polyacetal resin molded product 10 and the intermediate layer 20 can be more sufficiently peeled off. It can be suppressed. The lower limit of the melt flow rate of the polyacetal resin is not particularly specified, but is preferably larger than 0 g / 10 minutes, more preferably 1.0 g / 10 minutes or more, and further preferably 1.5 g / 10 minutes or more. Is. Within such a range, the adhesive strength tends to be further improved.
Here, the melt flow rate refers to a value measured by a method conforming to the ASTM-D1238 standard.

The adhesive resin composition of the present invention preferably contains a polyacetal resin in an amount of 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. Further, the adhesive resin composition of the present invention preferably contains the polyacetal resin in a proportion of 70% by mass or less, more preferably in a proportion of 60% by mass or less, and in a proportion of 50% by mass or less. It is more preferably contained, more preferably 40% by mass or less, and even more preferably 35% by mass or less.
The adhesive resin composition of the present invention may contain only one type of polyacetal resin, or may contain two or more types of polyacetal resin. When two or more kinds are included, the total amount is preferably in the above range.

<Polyethylene resin>
The polyethylene resin contained in the adhesive resin composition of the present invention is not limited. As the polyethylene resin, for example, a high-density polyethylene resin, a medium-density polyethylene resin, a high-pressure method low-density polyethylene resin, a linear low-density polyethylene resin, an ultra-low-density polyethylene resin, or the like can be used.
Further, an acid-modified polyethylene resin or the like can be used. Here, the acid-modified polyethylene resin refers to a polyethylene resin graft-modified with an acid or an acid anhydride.

When an acid-modified polyethylene resin is used as the polyethylene resin, the modification rate of the polyethylene resin is not particularly limited, but the acid modification rate of the acid-modified polyethylene resin is 0.01 mass of the total mass of the acid-modified polyethylene resin. % Or more is preferable. By setting the acid denaturation rate to 0.01% by mass or more, the intermediate layer has better adhesiveness to the polyacetal resin molded product, so that peeling between the polyacetal resin molded product and the intermediate layer is more sufficiently suppressed. can do. The acid denaturation rate of the polyethylene resin is more preferably 0.05% by mass or more, further preferably 0.10% by mass or more, still more preferably 0.15% by mass or more, and even more preferably 0. It is 20% by mass or more. The acid modification rate of the polyethylene resin is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, further preferably 0.50% by mass or less, and 0. It is more preferably 40% by mass or less. By setting the acid denaturation rate of the polyethylene resin to 2.0% by mass or less, the decomposition of the polyacetal resin is more effectively suppressed, and the amount of formaldehyde generated is more effectively reduced.
The maleic anhydride denaturation rate was measured by hot-pressing maleic anhydride-modified polyethylene at 180 ° C. to prepare a 100 μm film and measuring the infrared absorption spectrum. ^{Specifically, the ratio of the absorbance of the peak of 1790 cm -1} and the absorbance of the peak of 4250 cm ^-1 of the infrared absorption spectrum was obtained, and the value of the absorbance ratio based on the infrared spectrum prepared in advance and ¹ H-NMR were used. It was obtained from a calibration curve based on the correlation with the measured value of maleic anhydride denaturation rate. The number of maleic anhydride groups in the composition was calculated from the maleic anhydride denaturation rate.

The acid-modified polyethylene resin can be produced by uniformly mixing a polyethylene resin, an acid or an acid anhydride, and a radical generator, and graft-modifying the acid or acid anhydride with respect to the polyethylene resin. Specific examples of such a production method include a melt-kneading method using an extruder, a Banbury mixer, a kneader, etc., a solution method for dissolving in an appropriate solvent, a slurry method for suspending in an appropriate solvent, or so-called ki. The phase graft method and the like can be mentioned. The treatment temperature is appropriately selected in consideration of the deterioration of the polyethylene resin, the decomposition of the acid or acid anhydride, the decomposition temperature of the peroxide used, and the like. Taking the above-mentioned melt-kneading method as an example, the treatment temperature is selected. Is usually 190 to 350 ° C, and particularly preferably 200 to 300 ° C.

In producing the acid-modified polyethylene resin, a method of removing unreacted monomers (unsaturated carboxylic acid and its derivatives) and various components produced as by-products by heating or washing can be adopted.

Radical generators used for graft modification include dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and 2,5. -Dimethyl-2,5-di (t-butylperoxy) hexin-3,2,5-dimethyl-2,5-di (t-butylperoxy) hexane, lauroyl peroxide, t-butylperoxybenzoate, 1,1,3,3-Tetramethylbutylhydroperoxide, diisopropylbenzenehydroperoxide, t-butylcumyl peroxide, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, dit- Butyldiperoxyisophthalate, n-butyl-4,4-bis (t-butylperoxy) valerate, t-butylperoxybenzoate, t-butylperoxyacetate, cyclohexanone peroxide, t-butylperoxylaurate , Organic peroxides such as acetyl peroxide. Among these, those having a decomposition temperature of 160 to 200 ° C. for obtaining a half-life of 1 minute are preferable. When the decomposition temperature is 160 ° C. or higher, it is possible to sufficiently suppress that the decomposition reaction starts before the polyethylene resin as a raw material is sufficiently plasticized in the extruder, so that the reaction rate becomes higher, and conversely, the decomposition temperature is 200. When the temperature is lower than ° C., the reaction is likely to be completed in an extruder or the like, and the amount of unreacted unsaturated carboxylic acid and its derivative is reduced.

Examples of the polyethylene resin to be modified include high-density polyethylene resin, medium-density polyethylene resin, high-pressure method low-density polyethylene resin, linear low-density polyethylene resin, and ultra-low-density polyethylene resin. These may be used individually by 1 type or in combination of 2 or more type.

Examples of the acid that modifies the polyethylene resin include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and tetrahydrophthalic acid. These may be used individually by 1 type or in combination of 2 or more type.

Examples of the acid anhydride that modifies the polyethylene resin include unsaturated carboxylic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, nadic acid anhydride, and methyl nadic acid anhydride. These may be used individually by 1 type or in combination of 2 or more type.

Among the acid-modified polyethylene resins, maleic anhydride graft-modified polyethylene resin is particularly preferable. In this case, the decomposition of the polyacetal resin in the intermediate layer can be more sufficiently suppressed as compared with the case where the acid-modified polyethylene resin is an acid-modified polyethylene resin other than the maleic anhydride graft-modified polyethylene resin.

The density of the polyethylene resin is preferably 0.970 g / cm ³ or less, more preferably 0.965 g / cm ³ or less, and more preferably 0.954 g / cm ³ or less. By setting the content to 0.970 g / cm ³ or less, the intermediate layer can have better adhesiveness to the polyacetal resin molded product. The density of the polyethylene resin is more preferably 0.940 g / cm ³ or less. The density of the polyethylene resin is preferably 0.912 g / cm ³ or more, more preferably 0.925 g / cm ³ or more. By setting the density of the polyethylene resin to 0.925 g / cm ³ or more, the fuel oil swelling degree tends to be improved. Here, the density of the polyethylene resin refers to a value measured by a method based on JIS K7112.

The melt flow rate of the polyethylene resin measured under the conditions of 190 ° C. and 2.16 kg load is preferably 50 g / 10 minutes or less, more preferably 10 g / min or less, and 2.5 g / 10 minutes or less. It is more preferably 1.5 g / 10 minutes or less, further preferably 1.0 g / 10 minutes or less, and further preferably 0.7 g / 10 minutes or less. preferable. In particular, when the melt flow rate of the polyethylene resin measured under the conditions of 190 ° C. and 2.16 kg load is 2.5 g / 10 minutes or less, the melt flow rate exceeds 2.5 g / 10 minutes, as compared with the case where the melt flow rate exceeds 2.5 g / 10 minutes. The intermediate layer can have better adhesiveness to the polyethylene resin molded product, and peeling between the polyacetal resin molded product and the intermediate layer can be more sufficiently suppressed. The lower limit of the flow rate of the polyethylene resin is not particularly specified, but is preferably larger than 0 g / 10 minutes, more preferably 0.1 g / 10 minutes or more, and further preferably 0.2 g / 10 minutes or more. be.
In the present invention, the difference in melt flow rate between the polyacetal resin and the polyethylene resin contained in the adhesive resin composition measured under the conditions of 190 ° C. and 2.16 kg load is 1.0 to 3.0 g / 10 minutes. It is preferably 1.5 to 2.5 g / 10 minutes. With such a configuration, the effect of the present invention is more effectively exhibited.

The adhesive resin composition of the present invention preferably contains a polyethylene resin in an amount of 30% by mass or more, more preferably 40% by mass or more, further preferably 50% by mass or more, and further containing 60% by mass or more. It is even more preferable, and it is even more preferable to contain 65% by mass or more. Further, the polyethylene resin is preferably contained in a proportion of 90% by mass or less, more preferably 80% by mass or less, and further preferably 75% by mass or less. The adhesive resin composition of the present invention may contain only one type of polyethylene resin, or may contain two or more types of polyethylene resin. When two or more kinds are included, the total amount is preferably in the above range.

<Polyamide dimerate with a melting point of 180 ° C or less>
The adhesive resin composition of the present invention contains a polyamide dimerate having a melting point of 180 ° C. or lower. The dimer acid polyamide is a polyamide obtained by reacting dimer acid with a diamine. Dimeric acid is a quantified version of unsaturated fatty acids such as oleic acid, linoleic acid, and erucic acid, and one of the typical ones is mainly a dibasic acid having 36 carbon atoms and / or a hydrogenated additive. In addition, it contains a small amount of a monobasic acid (monomer) having 18 carbon atoms and a tribasic acid (trimmer) having 54 carbon atoms. The melting point of the dimer acid polyamide used in the present invention is preferably 170 ° C. or lower, more preferably 160 ° C. or lower, further preferably 150 ° C. or lower, and even more preferably 140 ° C. or lower. The lower limit of the melting point is not particularly specified, but can be, for example, 100 ° C. or higher. The dimer acid polyamide having a melting point of 180 ° C. or lower may contain a structure derived from other than diamine acid and diamine, but is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 99% by mass or more. Is a structure derived from dimer acid and diamine.

The amine value of the dimer acid polyamide in the present invention is preferably 2 mgKOH / g or more, and more preferably 2.5 mgKOH / g or more. Within such a range, the generation of formaldehyde can be suppressed more effectively. The upper limit of the amine value is not particularly defined, but can be, for example, 5.0 mgKOH / g or less, and further, 4.0 mgKOH / g or less.

The blending amount of the polyamide dimerate in the adhesive resin composition of the present invention is 0.1 to 2.0% by mass based on the total amount of the polyacetal resin and the polyethylene resin. The lower limit of the blending amount is preferably 0.2% by mass or more, and more preferably 0.3% by mass or more. The upper limit of the blending amount is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, further preferably 0.9% by mass or less, and 0.7% by mass. % Or less is more preferable.
Only one kind of dimer acid polyamide may be used, or two or more kinds may be used. When two or more types are used, the total amount is preferably in the above range.

<Blend ratio>
The mass ratio of the polyacetal resin and the polyethylene resin in the adhesive resin composition of the present invention is 10 to 70:90 to 30, more preferably 20 to 60:80 to 40, and 25 to 50:75. It is more preferably ~ 50, and even more preferably 25-40: 75-60. The total amount of the polyacetal resin and the polyethylene resin is 100 parts by mass.

<Other ingredients>
The adhesive resin composition of the present invention may contain components other than the above-mentioned polyacetal resin, polyethylene resin and polyamide dimerate. Specific examples of other components include inorganic fillers, heat stabilizers, antioxidants, weather-resistant stabilizers, mold release agents, lubricants, crystal nucleating agents, antistatic agents, pigments and the like. These can be used alone or in combination of two or more.
In the adhesive resin composition of the present invention, the total of the polyacetal resin, polyethylene resin and polyamide dimerate preferably occupies 95% by mass or more, and preferably 97% by mass or more of the resin components constituting the composition. More preferably, it may be 99% by mass or more. The adhesive resin composition of the present invention preferably contains 90% by mass or more of a resin component, more preferably 95% by mass or more of a resin component, and further preferably 99% by mass or more of a resin component. preferable.
Further, the adhesive resin composition of the present invention can be configured to be substantially free of an inorganic filler. The term "substantially free" means that the content of the inorganic filler in the adhesive resin composition of the present invention is less than 1% by mass.
Further, the adhesive resin composition of the present invention comprises a dihydrazone compound (particularly, a dihydrazone compound (B1) represented by the general formula (1) specified in claim 1 of JP-A-2017-0225257 and a general formula (2). ) Can be substantially free of the dihydrazone compound). The term "substantially free" means that the content of the dihydrazone compound is less than 0.02 parts by mass with respect to 100 parts by mass of the polyacetal resin, and is preferably 0.01 parts by mass or less.

In the present invention, the polyacetal resin molded body containing the polyacetal resin, the polyethylene resin molded body containing the polyethylene resin, and the polyacetal resin molded body and the polyethylene resin molded body are provided between the polyacetal resin molded body and the polyethylene resin molded body. Disclosed is a composite molded body having a polyethylene resin molded body and intermediate layers in contact with each other, wherein the intermediate layer is formed from the adhesive resin composition of the present invention.
Hereinafter, embodiments of the composite molded product of the present invention will be described in detail with reference to FIG. FIG. 1 is a cross-sectional view showing an embodiment of the composite molded product of the present invention.

As shown in FIG. 1, the composite molded body 100 is provided between the polyacetal resin molded body 10 containing the polyacetal resin, the polyethylene resin molded body 30 containing the polyethylene resin, the polyacetal resin molded body 10 and the polyethylene resin molded body 30. It has an intermediate layer 20 to be formed.

The intermediate layer 20 is formed from the adhesive resin composition of the present invention.

According to this composite molded body 100, it is possible to sufficiently suppress warpage and swelling after contact with the liquid organic compound.
Here, examples of the organic compound contained in the liquid organic compound include hydrocarbons, alcohols, and mixtures thereof.
Examples of the hydrocarbon include aromatic hydrocarbons such as toluene and aliphatic hydrocarbons such as isooctane.
Examples of alcohols include methanol and ethanol.

<Polyacetal resin molded product>
The polyacetal resin contained in the polyacetal resin molded body 10 is not particularly limited as long as it is a polyacetal resin having a divalent oxymethylene group, and even if it is a homopolymer containing only a divalent oxymethylene group as a constituent unit. For example, it may be a copolymer containing a divalent oxymethylene group and a divalent oxyethylene group as constituent units.

In the above polyacetal resin, the ratio of the oxyethylene group to 100 mol of the oxymethylene group is not particularly limited, and may be, for example, 0 to 5 mol.

In order to produce the polyacetal resin, trioxane is usually used as a main raw material. Further, in order to introduce an oxyethylene group into the polyacetal resin, for example, 1,3-dioxolane or ethylene oxide may be used as a comonomer.

The melt flow rate measured under the conditions of 190 ° C. and a 2.16 kg load of the polyacetal resin is not particularly limited, and the melt flow rate value may be, for example, 0.1 to 200 g / 10 minutes.

The polyacetal resin molded product 10 may contain a polyacetal resin. Therefore, the polyacetal resin molded product 10 may be composed of only the polyacetal resin, or may further contain additives in addition to the polyacetal resin. Examples of the additive include an inorganic filler, a heat stabilizer, an antioxidant, a weathering stabilizer, a mold release agent, a lubricant, a crystal nucleating agent, an antistatic agent, a pigment and the like. These can be used alone or in combination of two or more.
Further, in the present invention, the polyacetal resin molded product can be configured to be substantially free of an inorganic filler. The term "substantially free" means that the content of the inorganic filler in the polyacetal resin molded product is less than 1% by mass.
In the present invention, a part or all of the polyacetal resin contained in the polyacetal resin molded product and the polyacetal resin contained in the adhesive resin composition may be common or different.

<Polyethylene resin molded product>
The polyethylene resin contained in the polyethylene resin molded product 30 is not particularly limited as long as it is a polyethylene resin. As such a polyethylene resin, for example, a high-density polyethylene resin, a medium-density polyethylene resin, a high-pressure method low-density polyethylene resin, a linear low-density polyethylene resin, an ultra-low-density polyethylene resin, or the like can be used. The polyethylene resin contained in the polyethylene resin molded product may be one that has not been acid-modified or may be one that has been acid-modified. For example, the acid denaturation rate can be less than 0.01% by mass of the total mass of the polyethylene resin.
The polyethylene resin molded product 30 may contain a polyethylene resin. Therefore, the polyethylene resin molded product 30 may be composed of only the polyethylene resin, or may further contain additives in addition to the polyethylene resin. Examples of the additive include an inorganic filler, a heat stabilizer, an antioxidant, a weathering stabilizer, a mold release agent, a lubricant, a crystal nucleating agent, an antistatic agent, a pigment and the like. These can be used alone or in combination of two or more.
Further, in the present invention, the polyethylene resin molded product can be configured to be substantially free of an inorganic filler. The term "substantially free" means that the content of the inorganic filler in the polyethylene resin molded product is less than 1% by mass.
In the present invention, a part or all of the polyethylene resin contained in the polyethylene resin molded product and the polyethylene resin contained in the adhesive resin composition may be common or different.

Regarding the method for producing the composite molded product, the description in paragraphs 0077 to 0090 of JP-A-2017-08039 can be referred to, and these contents are incorporated in the present specification.

The composite molded body of the present invention is applied to, for example, a valve device, a recirculation line, a vent line, a flange for a fuel sender module, and a fuel tank connecting component such as a swivel tank adhered to an inner wall surface of a fuel tank. It is possible.

Hereinafter, the present invention will be described in more detail with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

<Polyacetal resin (POM)>
POM-1: Oxyethylene group is contained in a ratio of 1.6 mol to 100 mol of oxymethylene group, and melt flow rate (ASTM-D1238 standard: 190 ° C., 2.16 kg) is 2.5 g / 10 minutes. A certain acetal copolymer POM-2: oxyethylene group is contained in a ratio of 1.6 mol to 100 mol of oxymethylene group, and melt flow rate (ASTM-D1238 standard: 190 ° C., 2.16 kg) is 9.0 g / 10 minutes acetal copolymer POM-3: oxyethylene group is contained in a ratio of 1.6 mol to 100 mol of oxymethylene group, and 27 g of melt flow rate (ASTM-D1238 standard: 190 ° C., 2.16 kg) is contained. / 10 min Acetal Copolymer POM-4: Contains 1.6 mol of oxyethylene groups with respect to 100 mol of oxymethylene groups, and contains melt flow rate (ASTM-D1238 standard: 190 ° C, 2.16 kg). 57g / 10 min acetal copolymer

<Polyethylene resin (PE)>
PE-1: Density is 0.933 g / cm ³ (JIS K7112 compliant), Melt flow rate (ASTM-D1238 standard: 190 ° C., 2.16 kg) is 0.5 g / 10 minutes, and the acid modification rate is 0. 21% by mass acid-modified polyethylene resin PE-2: Density 0.933 g / cm ³ (JIS K7112 compliant), Melt flow rate (ASTM-D1238 standard: 190 ° C, 2.16 kg) 0.5 g / 10 minutes Acid-modified polyethylene resin PE-3 having an acid modification rate of 0.5% by mass: density of 0.933 g / cm ³ (JIS K7112 compliant), melt flow rate (ASTM-D1238 standard: 190 ° C., 2. 16 kg) is 0.5 g / 10 minutes, and the acid modification rate is 0% by mass. Acid-modified polyethylene resin PE-4: Density: 0.933 g / cm ³ (JIS K7112 compliant), Melt flow rate (ASTM-D1238) Standard: 190 ° C., 2.16 kg) is 1.8 g / 10 minutes, and the acid modification rate is 0.21 mass%. Acid-modified polyethylene resin PE-5: Density is 0.933 g / cm ³ (JIS K7112 compliant) ), Melt flow rate (ASTM-D1238 standard: 190 ° C., 2.16 kg) is 9.7 g / 10 minutes, and the acid modification rate is 0.21% by mass. Acid-modified polyethylene resin PE-6: Density is 0. .922 g / cm ³ (JIS K7112 compliant), melt flow rate (ASTM-D1238 standard: 190 ° C., 2.16 kg) is 0.5 g / 10 minutes, and acid modification rate is 0.21% by mass. Polyethylene resin PE-7: Density is 0.954 g / cm ³ (JIS K7112 compliant), Melt flow rate (ASTM-D1238 standard: 190 ° C, 2.16 kg) is 0.5 g / 10 minutes, and acid modification rate is high. 0.21% by mass acid-modified polyethylene resin

<Polyamide dimerate, etc.>
TXM-272: Polyamide dimerate (manufactured by T & K TOKA, trade name: tomide TXM-272, softening point 125 ° C., amine value 3.0 mgKOH / g)
1013B: Polyamide 6 (manufactured by Ube Industries, Ltd., UBE nylon 1013B, melting point 215 to 225 ° C.)
CM4000: Copolymerized Polyamide 6/66/610 (manufactured by Toray Industries, Inc., trade name: CM4000, melting point 140 ° C)
L16: Polyamide 12 (manufactured by EMS, trade name: grill amide L16, melting point 178 ° C.)

<Examples 1 to 16 and Comparative Examples 1 to 7>
A mixture of polyacetal resin, polyethylene resin, polyamide dimerate, etc. was mixed with a super mixer manufactured by Kawada Seisakusho Co., Ltd. in the blending amounts shown in Tables 1 to 3 (the unit of the numerical value of each component is parts by mass) to obtain a mixture. Later, this mixture is melt-kneaded and extruded with a twin-screw extruder (“PCM-30” manufactured by Ikekai Iron Works Co., Ltd., screw diameter 30 mm), and the strands discharged from the extruder are cooled in a water tank and cut with a pelletizer. , Examples 1 to 16 and Comparative Examples 1 to 7, respectively, were obtained.

<< Evaluation of Adhesiveness >>
The adhesive strength was measured according to the description in paragraphs 0110 to 0112 of JP-A-2017-08039. That is, in Example 1 of JP-A-2017-08039, the pellets obtained above were used as the pellets of the raw material for forming the intermediate layer, and the other steps were carried out in the same manner to ensure the adhesiveness of the intermediate layer to the polyacetal resin molded body. The test (adhesion strength against POM) and the adhesiveness test of the intermediate layer to the polyethylene resin molded body (adhesion strength against PE) were measured. The unit is indicated by N.

<< Mold Deposit (MD) >>
Using a mini mat M8 / 7A molding machine manufactured by Sumitomo Heavy Industries, Ltd., and using a drop mold as shown in FIG. 1 of JP2012-233129A, the cylinder temperature is 220 ° C and the mold temperature is 40 ° C. 000 shots were continuously molded, and after completion, the state of the mold deposits was visually observed and evaluated according to the following four grades A to D.
A: There is almost no mold deposits and the mold stainability is extremely good. B: There are a few mold deposits, but the mold stainability is good. C: There are many mold deposits and the mold stainability is poor. : Mold deposits are spread all over, and mold contamination is extremely poor.

<< Formaldehyde generation >>
The pellets obtained above are dried for 4 hours using a hot air dryer having a temperature of 80 ° C., and using an injection molding machine PS-40 manufactured by Nissei Resin Industry Co., Ltd. at a cylinder temperature of 215 ° C. and a mold temperature of 80 ° C. A flat plate test piece of 100 mm × 40 mm × 2 mm was formed. The obtained flat plate test piece is subjected to formaldehyde generation by the following method on the day after its molding, in accordance with the method described in the German Automobile Manufacturers Association Standard VDA275 (Automotive Interior Parts-Quantification of Formaldehyde Emission by Revised Flask Method). The amount (HCHO generation amount) was measured.
Specifically, 50 mL of distilled water was placed in a polyethylene container, the lid was closed with the test piece suspended in the air, heated at 60 ° C. for 3 hours in a closed state, and then left at room temperature for 60 minutes. The test piece was taken out, and the amount of formaldehyde absorbed in the distilled water in the polyethylene container was measured by the acetylacetone colorimetric method with an ultraviolet (UV) spectrometer.
The formaldehyde generation amount is shown as a ratio (mass ratio) of the formaldehyde generation amount of each Example and Comparative Example when the formaldehyde generation amount of Comparative Example 1 is 100.

<< Δb after staying at 230 ° C >>
5 g of pellets of polyamide dimerate or the like used above were heated at 230 ° C. for 1 minute with a hot press to prepare a sheet having a thickness of about 200 μm. This sheet was used as a reference. Similarly, 5 g of pellets of polyamide dimerate or the like used above were heated at 230 ° C. for 15 minutes with a hot press to prepare a sheet having a thickness of about 200 μm. Hue measurement was performed on each sheet using a spectrophotometer SE6000 manufactured by Nippon Denshoku Kogyo Co., Ltd. under the condition of a C light source viewing angle of 2 °, and the Δb value of the sheet after staying for 15 minutes was obtained based on the reference sheet. rice field.

As is clear from the results, when the adhesive resin composition of the present invention is used, the mold deposit during molding is suppressed while ensuring the adhesiveness to the polyacetal resin molded product and the polyethylene resin molded product, and the molded product The amount of formaldehyde generated was small, and the amount of black spot foreign matter was small (Examples 1 to 16).
On the other hand, when the polyamide dimerate was not contained or when the amount of the polyamide dimerate was small, the amount of formaldehyde generated increased (Comparative Examples 1 and 2). Further, when the blending amount of the polyacetal resin was small (Comparative Example 3), the adhesive strength to the polyacetal resin molded product was significantly inferior. Further, when a polyamide other than the polyamide dimerate was used (Comparative Examples 4 to 6), the mold deposit was inferior and the discoloration of the polyamide itself after retention was large. When the blending amount of the polyamide dimerate was large (Comparative Example 7), the adhesive strength was inferior. Also, the mold deposit was inferior.
Further, by increasing the ratio of the polyethylene resin to the total amount of the polyacetal resin and the polyethylene resin, the amount of formaldehyde generated can be effectively suppressed (Examples 1 to 3).
Further, by reducing the MFR of the polyacetal resin, it has become possible to further improve the adhesive strength to the polyacetal resin molded product and the polyethylene resin molded product (Examples 1, 4 to 6).
Further, by using an acid-modified polyethylene resin as the polyethylene resin, it has become possible to further improve the adhesive strength to the polyacetal resin molded product (Examples 1, 7, and 8).
Further, by lowering the MFR of the polyethylene resin, it became possible to further improve the adhesive strength to the polyethylene resin molded product (Examples 1, 9, and 10).

Production of Composite Mold The composite molded body was formed by insert two-color molding using the pellets obtained in Example 1, the pellets of the raw material for forming the polyacetal resin molded body, and the pellets of the raw material for forming the polyethylene resin molded body.
Iupital F20-01 manufactured by Mitsubishi Engineering Plastics was used as the pellet of the raw material for forming the polyacetal resin molded body. As the raw material pellet for the polyethylene resin molded product, Novatec HJ221) manufactured by Japan Polyethylene Corporation was used. The polyethylene resin used in the raw material pellets for polyethylene resin molded products is not acid-modified.

First, pellets of a raw material for a polyethylene resin molded body are injection-molded using an injection molding machine (DCE-140 manufactured by Nissei Resin Industry Co., Ltd.) under the conditions of a resin temperature of 200 ° C. and a mold temperature of 80 ° C., and 63 mm × 63 mm × 1 mm. A polyethylene resin molded product having a thickness of (thickness) was obtained. On the other hand, two common molds having the same shape were arranged on the rotating plate. On the other hand, a mold for forming an intermediate layer and a mold for forming a polyacetal resin molded body were prepared.

Next, the polyethylene resin molded product formed as described above was inserted into the mold cavity formed by one common mold and the intermediate layer forming mold. Next, the raw material for forming the intermediate layer was introduced into the mold cavity while heating under the conditions of a resin temperature of 230 ° C. and a mold temperature of 100 ° C., and then cooled. In this way, an intermediate layer was formed on the polyethylene resin molded product.

Next, the rotating plate is rotated, and the raw material for forming the polyacetal resin molded body is placed in the mold cavity formed by another common mold and the mold for forming the polyacetal resin molded body at a resin temperature of 230 ° C. and a mold temperature. It was introduced while heating under the condition of 100 ° C., and then cooled. In this way, a polyacetal resin molded product was formed on the intermediate layer.

As described above, a square plate-shaped composite molded body having dimensions of 63 mm × 63 mm × 3 mm (thickness) was obtained.

10 Polyacetal resin molded product 20 Intermediate layer 30 Polyethylene resin molded product 100 Composite molded product

Claims (7)

Contains polyacetal resin, polyethylene resin, and polyamide dimerate having a melting point of 180 ° C. or lower.
The content of the polyamide dimerate is 0.1 to 2.0% by mass of the total content of the polyacetal resin and the polyethylene resin.
An adhesive resin composition having a mass ratio of the polyacetal resin and the polyethylene resin of 10 to 70: 90 to 30. The adhesive resin composition according to claim 1, wherein the polyethylene resin contains an acid-modified polyethylene resin, and the acid modification rate of the acid-modified polyethylene resin is 0.01% by mass or more of the total mass of the acid-modified polyethylene resin. .. The adhesive resin composition according to claim 1 or 2, wherein the acid-modified polyethylene resin is a maleic anhydride graft-modified polyethylene resin. The adhesive resin composition according to any one of claims 1 to 3, wherein the melt flow rate of the polyacetal resin measured under the conditions of 190 ° C. and a 2.16 kg load is 30 g / 10 minutes or less. The adhesive resin composition according to any one of claims 1 to 3, wherein the melt flow rate of the polyethylene resin measured under the conditions of 190 ° C. and 2.16 kg load is 2.5 g / 10 minutes or less. The adhesive resin composition according to any one of claims 1 to 5, wherein the density of the polyethylene resin is 0.965 g / cm ^{3 or less.} A polyacetal resin molded body containing a polyacetal resin, a polyethylene resin molded body containing a polyethylene resin, and the polyacetal resin molded body and the polyethylene resin molded body provided between the polyacetal resin molded body and the polyethylene resin molded body, the polyacetal resin molded body and the polyethylene resin molded body. A composite molded body having an intermediate layer in contact with each other, wherein the intermediate layer is formed from the adhesive resin composition according to any one of claims 1 to 6.

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