JPH07316366A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain the resin composition comprising a specific polyacetal resin and an acid anhydride-modified polyolefin resin, improved in impact resistance and appearance without impairing the mechanical and thermal characteristics of the polyacetal resin, and useful for automotive parts, etc. CONSTITUTION:This resin composition comprises (A) 99-1 pts.wt. of a polyacetal resin containing >=10wt.% of a branched polyacetal resin having a branched structure in the molecular chain and having an OH group content of >=25mmol/ kg, and (B) 1-99 pts.wt. of an acid anhydride-modified polyolefin resin. The resin composition may preferably contain (C) an esterification catalyst such as a pyridine compound or a tertiary amine compound in an amount of <=5 pts.wt. per 100 pts.wt. of A+B in addition to the components A and B, or the component B may preferably be prepared by modifying 100 pts.wt. of the polyolefin resin with 0.01-30 pts.wt. of an acid anhydride.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention improves the affinity between resins of a polymer blend consisting of a polyacetal resin and a polyolefin resin, and improves mechanical properties of the polyacetal resin.
The present invention relates to a resin composition that has improved impact resistance without impairing thermal properties.

[0002]

2. Description of the Related Art Polyacetal resins have excellent characteristics in mechanical and thermal characteristics, electrical characteristics, slidability, moldability, and dimensional stability of molded products. , Electrical equipment such as structural materials and mechanical parts,
Widely used as automobile parts, precision machine parts, etc. However, there are drawbacks such as insufficient surface impact strength in a portion requiring high impact resistance such as a housing of a home electric appliance. In order to improve this point, for example, a method of blending a rubber-like component such as polyurethane or an olefin-based elastomer has been tried, but since the affinity between the added elastomer component and the polyacetal resin is not good, simply Dispersion failure occurs only by melt-kneading, the excellent properties of the polyacetal resin are impaired due to insufficient interfacial bonding strength between both resins, the surface layer of the molded product peels off, and sufficient impact resistance is obtained. There are drawbacks such as not being able to do so. In order to overcome this point, for example, a copolymer obtained by introducing a polar comonomer component such as methyl methacrylate into a polyolefin resin, or an improvement such as blending a resin containing a reactive glycidyl group in its molecular structure with a polyacetal resin has been improved. However, the impact resistance of polyacetal has not yet been improved enough to be put to practical use.

[0003]

Therefore, as a result of diligent studies on such points, the present inventors have found that a polyacetal resin is more likely to have a polyolefin resin having an acid anhydride group which is highly reactive with a polyacetal resin, and a hydroxyl group serving as a reaction site than usual. By blending a large amount of polyacetal resin (hereinafter referred to as hydroxyl-rich polyacetal resin), the affinity between the polyacetal resin and the polyolefin resin is improved, and the excellent mechanical and thermal properties of the polyacetal resin are not impaired. Succeeded in making a molding resin material with added impact resistance (Japanese Patent Application No. 4-349047, Japanese Patent Application No. 5-27675, Japanese Patent Application No. 5-1795).
No. 73, Japanese Patent Application No. 5-237767). Then, as a result of further study, it was found that, particularly when a branched type having a branched structure in the molecular chain is used as the hydroxyl group-rich polyacetal resin, a further great improvement effect is obtained, and the present invention is completed. Came to. That is, the present invention comprises (A) 99 to 1 part by weight of a polyacetal resin containing 10% by weight or more of a branched polyacetal resin having a branched structure in the molecular chain and having a hydroxyl group content of 25 mmol / kg or more, and (B) an acid anhydride. A resin composition comprising 1 to 99 parts by weight of a modified polyolefin resin.

The constituent components of the present invention will be described below. The component (A) of the present invention is a polyacetal resin containing a branched-type hydroxyl group-rich polyacetal resin described below. Here, the branched-type hydroxyl-rich polyacetal resin is a thermoplastic resin whose main component is a polymer compound having an oxymethylene unit (-CH ₂ O-) as a main repeating unit, and has a branched structure in the molecular chain, The hydroxyl group content is 25 mmol / kg or more. Similar to the commonly used polyacetal resin except that it has a branched structure,
Formaldehyde, or one or more of trioxane and tetraoxane, or the monomer and ethylene oxide, propylene oxide, oxacyclobutane, 1,
Cyclic ethers such as 3-dioxolane, 1,4-butanediol formal and diethylene glycol formal, cyclic esters such as β-propiolactone and γ-butyrolactone, and certain vinyl compounds can be used as monomers and comonomers. The branched polyacetal resin can be obtained by adding a small amount of a branching agent for producing a branched structure when the monomer and the comonomer are polymerized by a usual method. The degree of polymerization, the degree of branching, the copolymerization composition ratio, and the copolymerization type do not matter. As a method for producing the branched hydroxyl group-rich polyacetal resin, for example, when polymerizing trioxane and a small amount of ethylene oxide with a cationic initiator such as BF ₃ , a branching agent such as glycerin, glycidol, glycerol formal is added. There is a method for adding water, a small amount of a compound having a hydroxyl group such as ethylene glycol, etc., but the production method is not particularly limited,
The binding site of the hydroxyl group in the molecular chain is not particularly limited. The hydroxyl group content in the branched hydroxyl group-rich polyacetal resin is 25 mmol / kg or more, preferably 30 mmol / kg or more. If the hydroxyl group content is low, the effect of the present invention cannot be obtained. If the hydroxyl group content is 25 mmol / kg or more, part or all of the molecular terminals may be converted into ether bonds, ester bonds and the like. On the other hand, as for branching, even if a predetermined amount of a branching agent is added when polymerizing a branched-type hydroxyl-rich polyacetal resin, branching is not necessarily introduced into all the molecules, so depending on the production method, a linear polyacetal may be added. A resin may be contained in some cases, but this does not impair the effects of the present invention. Further, in order to balance the physical properties and moldability of the resin, it is possible to further add a linear polyacetal resin. The linear polyacetal resin referred to here is a thermoplastic resin mainly composed of a polymer compound having an oxymethylene unit (-CH ₂ O-) as a main repeating unit and having no oxymethylene chain branch structure. Is. The linear polyacetal resin is a resin obtained by polymerizing one or more types of formaldehyde, trioxane, tetraoxane, etc. by an ordinary method, a copolymer composed of two or more types of these, or the monomer and ethylene oxide. , Propylene oxide, oxacyclobutane, 1,3-dioxolane,
Cyclic ethers such as 1,4-butanediol formal and diethylene formal, cyclic esters such as β-propiolactone and γ-butyrolactone, or copolymers of certain vinyl compounds, etc., with a degree of polymerization or homopolymer There is no particular limitation on the copolymer, the copolymer composition ratio, the copolymer type, and the hydroxyl group content. Further, a part of the molecular end may be converted into an ether bond, an ester bond or the like. The effect of the present invention can be obtained when the component (A) of the present invention contains 10% by weight or more of the branched hydroxyl group-rich polyacetal resin. Also, when adding a linear polyacetal resin, the timing of addition is not particularly limited, and in some cases, a branched-type hydroxyl group-rich polyacetal resin and other components (B), (C), and (D) are mixed. After that, a method of further adding a linear polyacetal resin is also possible.

The component (B) of the present invention is an acid anhydride-modified polyolefin resin obtained by modifying a polyolefin resin with an acid anhydride. As the polyolefin-based resin used here, ethylene, propylene, butene, hexene, octene, nonene, decene, homopolymers of α-olefins such as dodecene, or random consisting of two or more of these,
Block or graft copolymer, or 1,4-
Non-conjugated dienes such as hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene and 2,5-norbonadiene, conjugated diene components such as butadiene, isoprene and piperylene, α, β-unsaturated acids such as acrylic acid and methacrylic acid Or a derivative thereof such as an ester thereof, an acrylonitrile, styrene, an aromatic vinyl compound such as α-methylstyrene, a vinyl ester such as vinyl acetate, a vinyl ether such as vinyl methyl ether or a comonomer component such as a derivative of these vinyl compounds. Random, block, or graft copolymers containing one or more of the above, and the degree of polymerization, the presence or absence of side chains or branches, the degree thereof, the copolymer composition ratio, and the like are irrelevant. Further, as the acid anhydride used for modification, unsaturated carboxylic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, nadic anhydride, methylnadic acid anhydride, and allyl succinic anhydride. Or one or more selected from derivatives thereof. Examples of the modification method include a method of reacting a polyolefin resin and an unsaturated carboxylic acid anhydride such as maleic anhydride or a derivative thereof with a radical initiator such as an appropriate organic peroxide in a solution state or a molten state by reaction. Is preferable, but the manufacturing method thereof is not particularly limited. Here, the blending amount of both components is the polyolefin resin.
0.01 to 30 parts by weight of acid anhydride is suitable for 100 parts by weight. When the amount of the effective acid anhydride in the acid anhydride-modified polyolefin resin is too small, the affinity between the polyacetal resin and the polyolefin resin is not sufficiently improved, so the effect of the present invention cannot be obtained, and it is too large. If it does, gelation may occur, resulting in poor dispersibility and poor molding. The blending ratio of the component (B) in the present invention is (A),
The component (B) is contained in an amount of 1 to 99 parts by weight, preferably 5 to 40 parts by weight, based on 100 parts by weight of both components (B). If the blending amount of the component (B) is too large, the properties of the polyacetal resin may be impaired.

The catalyst for promoting the esterification reaction of the component (C) used in the present invention is not always an essential component, but when added, more preferable results can be obtained in terms of impact resistance and mechanical strength. (C) component, pyridine derivatives such as pyridine, 4-dimethylaminopyridine, 4-pyrrolidinopyridine and salts thereof, triethylamine, trimethylamine, triethylenediamine, N, N'-dimethylpiperidine, benzylmethylamine, dimethylaniline, etc. Tertiary amines and derivatives thereof, quaternary ammonium salts such as trimethylbenzylammonium chloride and derivatives thereof, aliphatic or aromatic organic acids such as acetic acid and benzoic acid, sodium acetate, sodium lauryl sulfate, sodium paratoluenesulfonate, etc. Organic acid salts of, tetrabutyl zirconate, zirconium naphthate, tetrabutyl titanate, tetraoctyl titanate, tetraphenyl tin, zinc acetate, stannous oxalate, zinc naphthenate, iron acetyl acetate, naphthenate manganate , Triphenylantimony, tributylantimony, triphenylbismuth, dibutyltin dichloride, and other organometallic compounds; zinc chloride, magnesium titanate, magnesium zirconate, and various other metal compounds. Add one or more of these. Can be done. The amount of component (C) added is 5 per 100 parts by weight of the total of components (A) and (B).
Less than or equal to parts by weight is suitable. If the amount of catalyst is too large, it may cause discoloration or the like.

The filler of the component (D) used in the present invention is not always an essential component, but in order to obtain a molded product excellent in performance such as mechanical strength, heat resistance, dimensional stability and electrical properties. It is preferable to mix them. As the component (D), a fibrous, powdery, tabular or hollow filler is used depending on the purpose. As the fibrous filler, glass fiber, asbestos fiber, carbon fiber, silicon fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, further stainless steel,
Inorganic fibrous substances such as metal fibrous substances such as aluminum, titanium, copper and brass can be used. A particularly representative fibrous filler is glass fiber or carbon fiber. In addition, high melting point organic fibrous fibrous substances such as aromatic polyamide resin, fluororesin and acrylic resin can also be used. As the powdery or granular filler, carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, iron oxide, Titanium oxide, metal oxides such as alumina, metal sulfates such as calcium sulfate and barium sulfate, carbonates such as calcium carbonate, magnesium carbonate and dolomite, and other silicon carbide, silicon nitride, boron nitride, various metal powders, etc. Can be mentioned. Examples of the plate-like filler include mica, glass flakes, various metal foils and the like. Examples of the hollow filler include shirasu balloon, metal balloon, glass balloon and the like. The surface of these fillers treated with organic silane, organic borane, organic titanate, urethane or the like can also be preferably used. These fillers can be used alone or in combination of two or more. The amount of component (D) added is 10 parts based on 100 parts by weight of both (A) and (B).
The amount is 0 parts by weight or less, and if the amount added is too large, the moldability and toughness may be impaired, which is not preferable.

The composition of the present invention is prepared by melt mixing the components described in detail by various methods. For example, a branched-type hydroxyl-rich polyacetal resin and a linear polyacetal resin, an acid anhydride-modified polyolefin-based resin, melt-kneading a predetermined amount of a catalyst, and a method of cutting into pellets after cooling, each component of the There is no particular limitation on the mixing time and the method. At this time, if necessary, an antioxidant, an ultraviolet absorber, a photoprotective agent, a basic auxiliary agent, a nucleating agent, a plasticizer, a lubricant, an antistatic agent, a flame retardant,
Additives such as colorants can be added in arbitrary amounts within a range that does not impair the physical properties of the present invention. Further, the polymer of the present invention can be appropriately blended with other polymers as long as the physical properties thereof are not impaired. The composition obtained by the present invention can be molded by a usual method.

[0009]

The composition obtained according to the present invention has improved impact resistance while maintaining excellent properties of the polyacetal resin in thermal properties and mechanical strength by improving the affinity of the polyacetal resin and the polyolefin resin. The properties are remarkably improved, and there are no appearance defects or surface peeling of the molded product due to poor dispersion of the dispersed resin, and many applications can be expected.

[0010]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
First, the branched and straight chain type hydroxyl group-rich polyacetal resins used in the examples were prepared as follows. Trioxane, dioxolane, glycerol formal as a branching agent, and water were blended as shown in Table 1 and polymerized in an autoclave at a polymerization temperature to obtain branched-type hydroxyl-rich polyacetal resins I and II. In addition, the branching agent was incorporated by NMR measurement, and the calibration curve by GPC-LALLS (Low Angle Laser Light Scattering Detector) method was compared with the calibration curve of the linear polyacetal resin. Was confirmed. Similarly, as shown in Table 1, a linear-type hydroxyl-rich polyacetal resin was polymerized from trioxane, dioxolane, and water. Next, the content (mmol / kg) of hydroxyl groups per 1 kg of the branched and linear hydroxyl-rich polyacetal resins was measured by the NMR method.
The results are shown in Table 1.

[0011]

[Table 1]

Example 1 (A) 75 parts by weight of branched-type hydroxyl group-rich polyacetal resin I (hydroxyl group content 100 mmol / kg) and 100 parts by weight of polypropylene resin (Hipol J440, manufactured by Mitsui Petrochemical Industry Co., Ltd.) were dried. (B) Maleic anhydride modified polypropylene I modified with 10 parts by weight of maleic acid 25 parts by weight of polypropylene I are mixed and mixed with 30 mm of 2
Set temperature 190 ° C with screw extruder, screw rotation speed 80 rpm
Was melt-kneaded and pelletized. Then, a test piece was molded from the pellet by an injection molding machine, and the following Izod impact strength and surface layer peeling test were evaluated. The results are shown in Table 2. [Izod impact strength] Notched impact strength (kgf · cm / cm) was measured according to ASTM D256. [Surface layer peeling test] Stick cellophane tape on the surface of the test piece,
After peeling, the state of peeling was visually evaluated, and those in which peeling was not observed were marked with ◯, and those in which peeling was observed were marked with x. Example 2 (A) A test piece was prepared in the same manner as in Example 1 except that 75 parts by weight of a branched hydroxyl group-rich polyacetal resin II having a hydroxyl group content of 260 mmol / kg was used instead of the branched type hydroxyl group-rich polyacetal resin I. Created and evaluated in the same manner. The evaluation results are shown in Table 2. Comparative Example 1 (A) A test piece was prepared in the same manner as in Example 2 except that 75 parts by weight of a linear hydroxyl group-rich polyacetal resin having a hydroxyl group content of 100 mmol / kg was used instead of the branched type hydroxyl group-rich hydroxyl group polyacetal resin II. It evaluated similarly. The evaluation results are shown in Table 2. Comparative Example 2 (A) Instead of the straight chain type hydroxyl group-rich polyacetal resin, a general polyacetal resin (hydroxyl group content 14 mmol / kg) was used.
Test pieces were prepared and evaluated in the same manner as in Comparative Example 1 except that the parts by weight were blended. The evaluation results are shown in Table 2. Examples 3 and 4 As shown in Table 1, test pieces were prepared and evaluated in the same manner as in Example 1 except that the compounding amount of the (A) branched-type hydroxyl group-rich polyacetal resin I was changed. The composition and the evaluation results are shown in Table 2. Example 5, Comparative Example 3 As a component (A), a branched hydroxyl group-rich polyacetal resin I is used.
A test piece was prepared and evaluated in the same manner as in Example 1 except that and a general polyacetal resin were used in combination. The composition and the evaluation results are shown in Table 2. Example 6, Comparative Example 4 As the component (A), a branched hydroxyl group-rich polyacetal resin II is used.
Test pieces were prepared and evaluated in the same manner as in the above-mentioned Examples and Comparative Examples, except that was used together with the general polyacetal resin. The composition and the evaluation results are shown in Table 2. Comparative Example 5 A test piece was prepared and evaluated in the same manner as in the above Examples and Comparative Examples except that a straight chain type hydroxyl group-rich polyacetal resin and a general polyacetal resin were used together as the component (A). The composition and the evaluation results are shown in Table 2.

Example 7 (B) Instead of the maleic anhydride modified polypropylene I, the maleic anhydride modified rate was changed to 5 parts by weight based on 100 parts by weight of polypropylene.
A test piece was prepared in the same manner as in Example 1 except that
evaluated. The results are shown in Table 3. Example 8 As a component (A), a branched hydroxyl group-rich polyacetal resin I
Example 7 except that the general polyacetal resin was used in combination with
Test pieces were prepared in the same manner as above and evaluated in the same manner. Table 3 shows the composition and the evaluation results. Example 9 (B) Instead of the maleic anhydride-modified polypropylene II, the maleic anhydride modification rate was based on 100 parts by weight of polypropylene.
25 parts by weight of maleic anhydride modified polypropylene III
A test piece was prepared in the same manner as in Example 8 except that
It evaluated similarly. The results are shown in Table 3. Comparative Example 6 (B) A test piece was prepared in the same manner as in Example 7 except that maleic acid modified polypropylene II was replaced with maleic acid modified polypropylene modified with 10 parts by weight of maleic acid based on 100 parts by weight of polypropylene. It was produced and evaluated in the same manner. The results are shown in Table 3. Comparative Examples 7 and 8 Test pieces were prepared and evaluated in the same manner as in Examples 7 and 9 except that the component (A) was replaced with a general polyacetal resin. The composition and the results are shown in Table 3.

Examples 10 to 12 Dimethylaminopyridine was further added as a catalyst to Example 8, and test pieces were prepared in the same manner as in Example 8 and evaluated in the same manner. Table 4 shows the composition and the evaluation results. Comparative Example 9 A test piece was prepared and evaluated in the same manner as in Example 11 except that only the general polyacetal resin was used as the component (A). Table 4 shows the composition and the evaluation results. Examples 13 and 14 (C) Test pieces were prepared and evaluated in the same manner as in the above Examples except that triethylenediamine or sodium acetate was used as the catalyst component. Table 4 shows the composition and evaluation results.
Shown in.

Example 15 (B) Instead of the maleic anhydride-modified polypropylene I, a maleic anhydride-modified EPR modified with 10 parts by weight of maleic anhydride per 100 parts by weight of ethylene-propylene copolymer (EPR) was used. A test piece was prepared and evaluated in the same manner as in Example 6 except that it was not used. The evaluation results are shown in Table 5. Comparative Example 10 (B) Unmodified EPR in place of maleic anhydride modified EPR
A test piece was prepared in the same manner as in Example 15 except that
evaluated. The evaluation results are shown in Table 5. Comparative Examples 11 and 12 Test pieces were prepared and evaluated in the same manner as in Example 15 except that a straight chain type hydroxyl group-rich polyacetal resin or a general polyacetal resin was used as the component (A). Table 5 shows the composition and the evaluation results.

Examples 16 to 17 and Comparative Examples 13 to 14 Further, the case of incorporating glass fiber as the component (D) was evaluated in the same manner as in the above Examples and Comparative Examples. Table 6 shows the composition and the evaluation results. Examples 18 to 20 (D) Glass beads instead of glass fiber, mica,
In the case where the glass balloon and the glass balloon were blended, test pieces were prepared in the same manner as in the above-mentioned Examples and Comparative Examples, and evaluated in the same manner. Table 6 shows the composition and the evaluation results. Example 21 A test piece was prepared and evaluated in the same manner as in the above Examples and Comparative Examples in the case where glass fiber and glass balloon were used in combination as the component (D). Table 6 shows the composition and the evaluation results.

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

[Table 4]

[0020]

[Table 5]

[0021]

[Table 6]

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Claims (6)

[Claims] 1. A branched polyacetal resin having a branched structure in the molecular chain (A) and having a hydroxyl group content of 25 mmol / kg or more.
99 to 1 parts by weight of polyacetal resin containing 10% by weight or more
(B) A resin composition comprising 1 to 99 parts by weight of an acid anhydride-modified polyolefin resin. 2. The resin composition according to claim 1, further comprising 5 parts by weight or less of the esterification reaction catalyst (C) with respect to a total of 100 parts by weight of the component (A) and the component (B). 3. A filler selected from (D) a fibrous filler, a granular filler, a plate-like filler and a hollow filler, relative to 100 parts by weight of the total of the components (A) and (B). The resin composition according to claim 1 or 2, which comprises 100 parts by weight or less of a filler composed of one or more kinds. 4. The (B) acid anhydride-modified polyolefin-based resin comprises 100 parts by weight of the polyolefin-based resin as 0.01% of acid anhydride.
The resin composition according to any one of claims 1 to 3, which has been modified with 30 to 30 parts by weight. 5. The (C) esterification reaction catalyst is one or more selected from the group consisting of pyridines or derivatives thereof or salts thereof, and tertiary amines or derivatives thereof. 4. The resin composition according to any one of 4 above. 6. (C) The esterification reaction catalyst comprises a quaternary ammonium salt or its derivative, an aliphatic organic acid, an aromatic organic acid or a salt thereof, an organometallic compound, zinc chloride, magnesium titanate and magnesium zirconate. It is 1 type (s) or 2 or more types selected from the group consisting of.
The resin composition according to claim 1.