JPH08165405A - Polyacetal polymer composition and molded product therefrom - Google Patents

Abstract

PURPOSE: To provide a polyacetal polymer composition which gives molded products improved in shock resistance and elongation and has a specific gravity reduced in comparison with the polyacetal homopolymer. CONSTITUTION: This polyacetal polymer composition is obtained by polymerizing (a) formaldehyde in the presence of (b) a specific block copolymer so that the weight ratio of (a)/(b) may be adjusted to 40/60-98/2. This block copolymer (b) has the block constitution of following (A)/(B) or (C)/(D) and bears hydroxyl groups on its chain terminals: the block (A), an aromatic vinyl polymer block or hydrogenated polybutadiene block (1,2-bonds=less than 30%); block (B), hydrogenated polyisoprene block, hydrogenated polybutadiene block (1,2-bonds = 30-80%) or hydrogenated isoprene/butadiene copolymer block; block (C), aromatic vinyl polymer block; and block (D), polyisobutylene block.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyacetal polymer composition having excellent mechanical properties and a small specific gravity, and a molded article made from the same.

[0002]

2. Description of the Related Art Polyacetal polymers have well-balanced properties among general-purpose engineering plastics and are widely used in electric and electronic parts, automobiles, transportation equipment parts, building materials and the like. However, the polyacetal polymer has drawbacks such as a relatively large specific gravity of about 1.42 and a slightly low impact resistance value.
Improvements on them are required.

[0003]

A polymer alloy with an elastomer is considered as a method for solving the above-mentioned drawbacks of the polyacetal polymer. However, since the polyacetal polymer is crystalline, its compatibility with other polymers is low, and as a result, in the polymer alloy,
The mechanical properties such as elongation and impact resistance are rather deteriorated, and the obtained molded product tends to be inhomogeneous. Therefore, impact modifiers applicable to polyacetal polymers are limited to some of polybutadiene, polyurethane and the like, and the improvement of mechanical properties has not been sufficiently achieved at present.

One of the objects of the present invention is to provide a polyacetal-based polymer composition which improves the tensile properties and impact resistance of the polyacetal-based polymer and realizes a low specific gravity without the above drawbacks. Especially. Another object of the present invention is to provide a molded article made of a polyacetal polymer having improved tensile properties and impact resistance and having a low specific gravity.

[0005]

According to the present invention, one of the above objects is to produce a polyacetal polymer by polymerizing formaldehyde (a). Polymer block and 1,
2-one or more of at least one block (A) selected from the group consisting of hydrogenated polybutadiene blocks in which polybutadiene having a bonding amount of less than 30% is hydrogenated,
Hydrogenated polyisoprene block, 1,2-bond content 30 ~
Hydrogenated polybutadiene block in the form of 80% polybutadiene hydrogenated and hydrogenated isoprene in the form of hydrogenated isoprene / butadiene random copolymer /
Or at least one block (B) selected from the group consisting of butadiene copolymer blocks, or at least one aromatic vinyl compound polymer block (C) and a polyisobutylene block ( A block copolymer (b) containing at least one of D) and having a hydroxyl group at the terminal, in which the weight ratio of formaldehyde (a) to block copolymer (b) is (a) / (b). Four
This is achieved by providing a polyacetal-based polymer composition obtained by adding it at a ratio within the range of 0/60 to 98/2. Further, according to the present invention, the above-mentioned other object is achieved by providing a molded article made of the above polyacetal polymer composition. The present invention will be described in detail below.

The block copolymer which is the component (b) in the present invention is a hydrogenated polybutadiene block obtained by hydrogenating an aromatic vinyl compound type polymer block and a polybutadiene having a 1,2-bond content of less than 30%. At least one block (A) selected from the group consisting of hydrogenated polyisoprene block and hydrogenated polybutadiene block in the form of hydrogenated polybutadiene having a 1,2-bond content of 30 to 80% And a random copolymer of isoprene / butadiene containing one or more of at least one block (B) selected from the group consisting of hydrogenated isoprene / butadiene copolymer blocks in hydrogenated form, and a molecule One or more of a block copolymer (b-1) having a hydroxyl group at the terminal of the main chain and an aromatic vinyl compound-based polymer block (C) Polyisobutylene block (D)
And a block copolymer (b-2) containing a hydroxyl group at the terminal of the main chain of the molecule. As the block copolymer (b), a block copolymer (b-
At least one selected from the group consisting of 1) and (b-2) can be used.

Examples of the block copolymer (b-1) include those represented by any one of the following formulas.

(W-X) _k- OH (X-W) _l- OH W '-(X-W) _m- OH X'-(W-X) _n- OH

(In the formulas, W and W'represent the block (A), X and X'represent the block (B), k, l, m and n each represent an integer of 1 or more, OH represents a hydroxyl group)

The number of repetitions k, l, m and n of the block (A) and the block (B) in the block copolymer (b-1) can be arbitrarily determined, but is usually an integer within the range of 1 to 5. Preferably there is.

The block (A) has an aromatic vinyl compound polymer block (A-1) and a 1,2-bond content of 30.
% Of polybutadiene is at least one block selected from the group consisting of hydrogenated polybutadiene blocks (A-2) in a hydrogenated form. The block (A-
1) is a block composed of a polymer composed of an aromatic vinyl compound as a main monomer component. As the aromatic vinyl compound, styrene, α-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-
One or more selected from t-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene and the like, but styrene is particularly preferable. The block (A-
2) has a 1,2-bond content of less than 30% (preferably 25).
% Or less) is a hydrogenated polybutadiene block in a hydrogenated form. The polybutadiene portion before hydrogenation is composed of a monomer unit mainly composed of a butadiene unit, and 70 mol% or more (preferably 75 to 100 mol%) of the butadiene unit accounts for a 2-butene-1,4-diyl group (-CH _{2 -CH = CH-CH 2 -} ; 1,4-bonded butadiene unit), less than 30 mol% (preferably 25-0 mol%) of vinyl ethylene group [-CH (CH =
CH ₂ ) —CH ₂ —; 1,2-bond butadiene unit].

The block (B) is a hydrogenated polyisoprene block (B-1), a hydrogenated polybutadiene block (B-2) in the form of hydrogenated polybutadiene having a 1,2-bond content of 30 to 80%, and Hydrogenated isoprene / isoprene / butadiene random copolymer
It is at least one block selected from the group consisting of butadiene copolymer block (B-3). The hydrogenated polyisoprene block (B-1) is a block obtained by hydrogenating polyisoprene composed of a monomer unit mainly composed of isoprene units. The isoprene unit is
2-Methyl-2-butene-1,4-diyl group [—CH ₂
—C (CH ₃ ) ═CH—CH ₂ —; 1,4-bond isoprene unit], isopropenyl ethylene group [—CH [C (CH
₃ ) = CH ₂ ] -CH _2- ; 3,4-bond isoprene unit] and 1-methyl-1-vinylethylene group [-C
(CH ₃ ) (CH═CH ₂ ) —CH ₂ —; 1,2-bond isoprene unit]. The block (B-2) is a hydrogenated polybutadiene block in which polybutadiene having a 1,2-bond content of 30 to 80% (preferably 35 to 60%) is hydrogenated. The polybutadiene portion before hydrogenation is composed of a monomer unit having a butadiene unit as a main component, and 70 to 20 mol% (preferably 65 to 40 mol%) of the butadiene unit accounts for a 2-butene-1,4-diyl group (- CH ₂ -C
H = CH—CH ₂ —; 1,4-bond butadiene unit)
, And the 30 to 80 mol% (preferably 35 to 60 mol%) of vinyl ethylene group _{[-CH (CH = CH 2)} -CH 2
-; 1,2-bond butadiene unit]. The block (B-3) is a hydrogenated isoprene / butadiene copolymer block obtained by hydrogenating a random copolymer of isoprene / butadiene composed of a monomer unit mainly containing isoprene units and butadiene units. The isoprene unit includes 2-methyl-2-butene-1,4-diyl group, isopropenylethylene group and 1-methyl-1-
At least 1 selected from the group consisting of vinyl ethylene groups
A group of species, the butadiene unit being 2-butene-1,4
A diyl group and / or a vinylethylene group.

Blocks (A-2), (B-1), (B-
The degree of hydrogenation to the carbon-carbon double bond portion in 2) and (B-3) may be partial hydrogenation or complete hydrogenation. However, in the block copolymer (b-1), 50% or more, especially 80% or more of the carbon-carbon double bonds in the isoprene unit and the butadiene unit are hydrogenated (that is, the degree of unsaturation is 50%). In the following, it is particularly preferably 20% or less) because the heat deterioration resistance, weather resistance and the like are improved, and the performance is exhibited in the obtained polymer composition and molded article. In the block copolymer (b-1), at least one block selected from the group consisting of blocks (B-1) and (B-3) among the blocks (B) has an effect of improving impact resistance. Is particularly preferable because it becomes large. From the viewpoint of this effect, the molar ratio of isoprene unit / butadiene unit is within the range of 1/9 to 9/1,
Especially, the block (B-3) within the range of 3/7 to 7/3 is particularly preferable.

Examples of the block copolymer (b-2) include those represented by any one of the following formulas.

HO-Y '-(Z-Y) _p- OH HO-Z'-(YZ) _q- OH

(In each formula, Y and Y'represent the block (C), Z and Z'represent the block (D), p and q each represent an integer of 1 or more, and HO and OH represent Each represents a hydroxyl group)

The number of repetitions p and q of the block (C) and the block (D) in the block copolymer (b-2) can be arbitrarily determined, but it is usually preferably an integer within the range of 1 to 5. .

The block (C) is a block composed of a polymer composed mainly of an aromatic vinyl compound. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, 4-methylstyrene, 4
-Propylstyrene, 4-t-butylstyrene, 4-chlorostyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, etc. are selected from one kind or two or more kinds,
Styrene is particularly preferred. The block (D) is an isobutylene unit _{[-C (CH 3) 2 -CH} 2 -] , which is a polyisobutylene block whose main monomer unit.

The hydroxyl group in the block copolymer (b-1) may be bonded to either the terminal of the block (A) or the terminal of the block (B), and the hydroxyl group in the block copolymer (b-2). May be bonded to either the terminal of the block (C) or the terminal of the block (D), but these hydroxyl groups must be bonded to the terminal of the hard block, block (A) or block (C). Is preferably used, and a block bonded to the end of an aromatic vinyl compound polymer block (particularly polystyrene block) is more preferably used. The content of the terminal hydroxyl group is preferably 0.5 or more, and particularly preferably 0.6 to 2 per molecule of the block copolymer (b). When a block copolymer having no hydroxyl group at the end is used in place of the block copolymer (b), the resulting polyacetal polymer composition and molded article have insufficient impact resistance and elongation. Become.

The number average molecular weight of the block (A) in the block copolymer (b-1) and the block copolymer (b)
The number average molecular weight of the block (C) in -2) is preferably in the range of 4,000 to 50,000.
The number average molecular weight of the block (B) in the block copolymer (b-1) and the number average molecular weight of the block (D) in the block copolymer (b-2) are each 1000.
It is preferably in the range of 0 to 100,000. Furthermore, the number average molecular weight of the block copolymer (b-1) and the number average molecular weight of the block copolymer (b-2) are 14 respectively.
It is preferably in the range of 000 to 150,000. The ratio of the sum of the weight of the block (A) / the sum of the weight of the block (B) in the block copolymer (b-1), and the sum of the weight of the block (C) in the block copolymer (b-2) / There is no particular limitation on the ratio of the sum of the weights of the blocks (D), but those having a range of 1/9 to 7/3 are preferably used. Further, the block copolymer (b) used in the present invention may be one type or two or more types, for example, the block copolymers (b-1) and (b-
It is possible to use with 2) together.

The above block copolymer (b-1)
Can be produced, for example, by an anionic polymerization method. In such a production method, for example, a living polymer of a block copolymer type is obtained according to an anion living polymerization method using a usual organic alkali metal catalyst, and after forming a hydroxyl group at the active terminal portion, it is hydrogenated,
A block copolymer (b-1) is obtained. Formula (W-X)
_k- OH or W '-(X-W) _m- OH (W in each formula,
W ′, X, OH, k and m are as defined above), and the block copolymer type living polymer giving a block copolymer represented by, for example, n-butyllithium, s-butyllithium, etc. Using a lithium compound as a polymerization initiator and a saturated aliphatic hydrocarbon compound such as hexane, heptane, or cyclohexane or an aromatic hydrocarbon compound such as benzene or toluene as a solvent, 30 to 30
Aromatic vinyl compound (monomer) under the temperature condition of 60 ℃
Alternatively, a living polymer is obtained by anionically polymerizing butadiene (monomer), and then the living polymer is used as an initiator to produce isoprene (monomer) and / or
Alternatively, a binary block copolymer type living polymer is obtained by anionically polymerizing butadiene (monomer), and if necessary, anionic polymerization of the aromatic vinyl compound (monomer) or butadiene (monomer). A ternary block copolymer-type living polymer is obtained by carrying out the above process, and if necessary, anionic polymerization of the above isoprene (monomer) and / or butadiene (monomer) and the above aromatic vinyl compound (monomer). Alternatively, it can be produced by sequentially repeating anionic polymerization of butadiene (monomer).

Formula (X-W) _l -OH or X '-(W-
X) _n —OH (in each formula, W, X, X ′, OH, 1 and n)
Is as defined above), a block copolymer type living polymer giving a block copolymer represented by
For example, an alkyllithium compound such as n-butyllithium or s-butyllithium is used as a polymerization initiator, and a saturated aliphatic hydrocarbon compound such as hexane, heptane or cyclohexane or an aromatic hydrocarbon compound such as benzene or toluene is used as a solvent. Under the temperature condition of 30 to 60 ° C., isoprene (monomer) and / or butadiene (monomer)
To obtain a living polymer by anionic polymerization, followed by anionic polymerization of an aromatic vinyl compound (monomer) or butadiene (monomer) using the living polymer as an initiator to form a binary block copolymer type Living polymer of the above, and if necessary, the above isoprene (monomer) and / or butadiene (monomer)
By performing anionic polymerization of (3) to obtain a ternary block copolymer type living polymer, and further, if necessary, anionic polymerization of the aromatic vinyl compound (monomer) or butadiene (monomer) and the isoprene (monomer). It can be produced by sequentially repeating anionic polymerization of (body) and / or butadiene (monomer).

The anionic polymerization of the above-mentioned butadiene (monomer) is carried out in the presence of an appropriate amount of a vinylating agent such as tetraethylenediamine to adjust the amount of 1,2-bond in the polybutadiene block to be 30 to 30. It can be increased to 80%. Similarly, by carrying out anionic polymerization of isoprene (monomer) in the presence of an appropriate amount of a vinylating agent, the amount of 3,4-bonds in the polyisoprene block formed is increased to 30 to 80%. You can also

When the block copolymer-type living polymer obtained as described above reaches the desired main chain structure and molecular weight, epoxides such as ethylene oxide or propylene oxide are added, and then alcohols,
By stopping the polymerization by adding an active hydrogen compound such as carboxylic acid and water, an unhydrogenated block copolymer having a hydroxyl group at the terminal can be obtained.

Subsequently, the obtained unhydrogenated block copolymer is hydrogenated. As the hydrogenation catalyst, a homogeneous catalyst or a heterogeneous catalyst can be used. When a homogeneous catalyst is used, an organic transition metal catalyst (for example, nickel acetylacetonate, cobalt acetylacetonate, nickel naphthenate, cobalt naphthenate, etc.) and an alkyl compound of a metal such as aluminum, an alkali metal or an alkaline earth metal is used. A homogeneous hydrogenation catalyst such as a Ziegler catalyst composed of a combination of about 0.01 to 0.1 mol% with respect to the carbon-carbon double bond contained in the unhydrogenated block polymer to be subjected to the hydrogenation reaction. Is suitable for use. The hydrogenation reaction can be carried out at a temperature of room temperature to 150 ° C. and a normal pressure to hydrogen pressure of 50 kg / cm ² , and is usually completed in about 1 to 50 hours. After the reaction was completed, acidic water was added to the reaction vessel and the mixture was vigorously stirred to dissolve the hydrogenation catalyst in water, the aqueous phase was removed from the two phases separated, and the solvent was distilled from the obtained organic phase. By removing, the target block copolymer (b-1)
Can be obtained.

When a heterogeneous catalyst is used, nickel, cobalt, palladium, rhodium, ruthenium, platinum and the like are used alone or on a carrier such as silica, diatomaceous earth, alumina or activated carbon, and then unhydrogenated. It is suitable to use it in an amount of 0.5 to 10% by weight based on the block polymer. The hydrogenation reaction can be carried out at a temperature of room temperature to 250 ° C. and a hydrogen pressure of atmospheric pressure to 200 kg / cm ² , and is usually completed in about 1 to 50 hours. After the reaction,
The catalyst was filtered off from the reaction mixture, and the solvent was distilled off from the obtained filtrate to obtain the target block copolymer (b-
1) can be obtained.

On the other hand, the block copolymer (b-2) can be produced by, for example, a cationic polymerization method. According to this production method, an unmodified block copolymer is obtained according to a usual method such as cationic living polymerization using 1,4-bis (1-methoxy-1-methylethyl) benzene, and then main chain A block copolymer (b-2) is obtained by forming a hydroxyl group at the terminal portion. For example, in the block copolymer (b-2), the formula H
O-Y '-(Z-Y) _p- OH (in the formula, Y, Y', Z,
p, HO and OH are as defined above), the outline of the production examples is as follows. 1,4-in a solvent consisting of cycloalkanes such as cyclohexane and methylcyclohexane, or alkyl halides such as methyl chloride and methylene chloride
Using bis (1-methoxy-1-methylethyl) benzene and titanium tetrachloride as an initiator, -10 ° C to-
After isobutylene (monomer) is cationically polymerized under a temperature condition of 90 ° C. to obtain a polyisobutylene type living polymer, and subsequently, N, N-dimethylacetamide is added,
The resulting living polymer is used as an initiator to cationically polymerize an aromatic vinyl compound (monomer) to give an aromatic vinyl compound-based polymer-polyisobutylene-aromatic vinyl compound-based triblock copolymer. A polymer type living polymer is produced. If necessary, by repeating the polymerization operation of isobutylene (monomer) or the polymerization operation of it and an aromatic vinyl compound (monomer), a living polymer of a block copolymer type of 5 or more and an odd number of blocks. Is generated. The ternary or more block copolymer-type living polymer thus produced is terminating with a chlorine atom at both ends of the main chain by stopping the reaction by means such as addition of methanol or temperature increase according to a conventional method. The above block copolymer is obtained. Then, the obtained block copolymer having chlorine atoms at both terminals is subjected to dehydrochlorination, hydroboration and oxidation to give a compound of formula HO-Y '-(Z-Y) _p- OH (wherein Y , Y ', Z, p, HO and OH are as defined above).

The polyacetal polymer composition of the present invention is the same as the ordinary polymerization method for obtaining a polyacetal polymer except that the above block copolymer (b) is present in the formaldehyde polymerization reaction system. Manufactured. In the polymerization reaction for obtaining the polyacetal polymer composition of the present invention, an anionic polymerization catalyst, a coordinated anionic polymerization catalyst or a cationic polymerization catalyst is usually used. The polymerization is generally carried out in an organic solvent. Further, in the polymerization, Japanese Patent Publication No. 35-9435 and Japanese Patent Publication No. 41-21
As described in Japanese Patent No. 638, etc., alcohol,
By adding a chain transfer agent such as carboxylic acid, it is possible to control the degree of polymerization of formaldehyde to a desired degree.

Typical examples of anionic polymerization catalysts or coordination anionic polymerization catalysts are alkali metals such as sodium and lithium; alkyl metal compounds such as s-butyl lithium; alkali metal complex compounds such as sodium / naphthalene; sodium methoxide and the like. Alkali metal alkoxides; amines such as n-butylamine and diethylamine; quaternary ammonium salts such as ammonium stearate and tetrabutylammonium acetate; and tetravalent organic tin compounds such as dibutyltin dilaurate, tributyltin chloride and diethyltin dilaurate. Further, as a typical example of the cationic polymerization catalyst, tin tetrachloride,
Tin tetrabromide, titanium tetrachloride, aluminum trichloride, zinc chloride, boron trifluoride, boron trifluoride diethyl etherate, perchloric acid, acetyl perchlorate, p-toluene sulfonic acid, triethyloxonium tetrafluoroborate, Examples thereof include triethylaluminum, diethylaluminum chloride and the like.

As the organic solvent, hexane, heptane,
Aliphatic hydrocarbons such as cyclohexane; Aromatic hydrocarbons such as benzene, toluene, xylene; Halogenated aliphatic hydrocarbons such as methylene chloride, ethylene chloride, carbon tetrachloride;
Halogenated aromatic hydrocarbons such as chlorobenzene and orthodichlorobenzene can be used. These organic solvents may be used alone or in combination of two or more. It is preferable that these organic solvent and formaldehyde are sufficiently dehydrated and purified.

The chain transfer agent (molecular weight adjusting agent) is preferably used after being uniformly dissolved or dispersed in the reaction system. As alcohol, methyl alcohol, ethyl alcohol, hexyl alcohol, cyclohexyl alcohol,
Benzyl alcohol and the like can be used, and as the carboxylic acid, formic acid, acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid and the like can be used.
The concentration of the chain transfer agent in the system is adjusted according to the molecular weight of the desired polyacetal polymer, and can be easily determined experimentally.

In the polymerization of the present invention, the weight ratio of formaldehyde (a) to block copolymer (b) used must be in the range of 98/2 to 40/60 in (a) / (b). Is. The proportion of formaldehyde is
When it is lower than 40% by weight based on the total weight of formaldehyde and block copolymer, excellent mechanical properties such as high strength and high elastic modulus inherent in the polyacetal polymer are lost. On the other hand, when the proportion of the block copolymer is less than 2% by weight based on the total weight of formaldehyde and the block copolymer, the impact resistance and elongation are improved, and the improvement effects such as low specific gravity are sufficiently obtained. I can't. From the point that particularly good results are obtained in terms of both retaining the excellent properties among the mechanical properties that the polyacetal-based polymer originally possesses, and improving the impact resistance and the elongation and reducing the specific gravity, formaldehyde is obtained. The weight ratio of (a) to the block copolymer (b) is 95/5 in (a) / (b).
It is preferably -50/50.

When formaldehyde is added to the reaction system in the present invention, the formaldehyde may be in the form of a trimer trioxane according to a polymerization method for obtaining an ordinary polyacetal polymer. Good. Further, in the present invention, formaldehyde may be partially replaced with another monomer copolymerizable with formaldehyde within a range that does not lose the effect of the present invention. Examples of the other monomer include ethylene oxide, propylene oxide, Epoxides such as butylene oxide; ethylene glycol formal, propylene glycol formal, 1,4-butanediol formal,
Mention may be made of cyclic ethers such as cyclic formal such as diethylene glycol formal. However, when the other monomer is used in combination, the number of moles is the number of moles of formaldehyde (when trioxane is used,
It is preferably not more than 50% with respect to the sum of the number of moles and the number of moles of formaldehyde converted to 3 moles).

The reaction temperature is generally set between −90 ° C. and 200 ° C., but in most cases, it is a temperature between −78 ° C. and 110 ° C. considering the freezing point and boiling point of the organic solvent. Is preferred. The reaction time is not particularly limited, but usually can be appropriately set within the range of 6 hours. The block copolymer (b) may be added to the reaction system before or during the polymerization reaction, but the block copolymer (b) may be added to the reaction system from the beginning of the polymerization reaction. It is preferable to make it exist. After a predetermined polymerization time, according to a general method for producing a polyacetal polymer, for example, the obtained reaction mixture is filtered, the obtained solid matter is washed with acetone, and then vacuum dried to obtain the target. A polyacetal polymer composition can be obtained. The hydroxyl group at the terminal of the hemiacetal-type molecule formed by the above-mentioned polymerization reaction is somewhat lacking in thermal stability. Therefore, if necessary, esterification, etherification, urethanization, etc., blocking of the polyacetal polymer. Stability may be improved by blocking the molecular ends according to known methods.

The polyacetal polymer composition of the present invention contains, if necessary, polyolefins such as polyethylene and polypropylene; other organic polymers such as polystyrene, reinforcing agents, fillers, antioxidants and mold release agents. Agent, colorant,
It may contain various additives such as an ultraviolet absorber, an antistatic agent, a crystal nucleating agent and a flame retardant.

The polymer composition of the present invention can be prepared by any molding method such as injection molding, extrusion molding, press molding, blow molding, extrusion blow molding, calender molding and cast molding.
It can be molded into any shape such as plate, sheet, film, pipe, etc. The molded product obtained in this way is used for various applications such as electrical parts, electronic parts, mechanical parts, automobile parts, daily necessities, etc. be able to.

[0037]

[Examples] The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. In addition,
In the following Examples and Comparative Examples, the block copolymers used as raw materials are shown by abbreviations, and the specific contents are shown in Table 1 below.

[0038]

[Table 1]

The polyacetal polymer composition or the polyacetal polymer obtained in each of the following Examples and Comparative Examples was molded into a test piece by the following method and subjected to various tests.

[Measurement of Tensile Elongation (Elasticity Judgment Test)] The obtained polymer composition or polymer was heated at a temperature of 2 with a Brabender.
After kneading and shredding at 20 ° C., a plate-shaped test piece was prepared by press molding at a temperature of 220 ° C. and a pressing pressure of 100 kg / cm ² . Using the obtained test piece,
The tensile elongation was measured according to JIS K7113.

[Measurement of Impact Resistance Value with Notch (Impact Resistance Judgment Test)] The obtained polymer composition or polymer was kneaded with a Brabender at a temperature of 220 ° C. and shredded, and then a temperature of 220 ° C. Then, an Izod test piece with a v-notch was prepared by press molding with a pressing pressure of 100 kg / cm ² . Using the obtained test piece, JIS K7110
The impact resistance value with notch was measured in accordance with.

[Measurement of Specific Gravity (Lightness Judgment Test)] Specific gravity was measured using a test piece of the same type as that prepared for the measurement of tensile elongation.

[Synthesis Example 1 of Block Copolymer (b)] 1000 g of sufficiently dehydrated cyclohexane, 15 g of styrene and 0.2 g of n-butyllithium were added to a pressure vessel equipped with a stirrer, and the mixture was kept at 40 ° C. for 1 hour. Polymerize, add 70 g of isoprene and polymerize at the same temperature for 1 hour.
g and polymerize at the same temperature for 1 hour, then add 0.14 g of ethylene oxide and react at the same temperature (modification of molecular end)
After that, 0.1 g of methanol was added to stop the reaction. The atmosphere of the reaction mixture in the pressure vessel thus obtained was replaced with hydrogen, 10 g of a diatomaceous earth-supported nickel catalyst was added, and then the mixture was heated to 1 kg under a hydrogen pressure of 15 kg / cm ^2.
Hydrogenation reaction was carried out at 50 ° C. for 5 hours. The reaction mixture obtained was diluted with cyclohexane, the supported catalyst was filtered off, and the filtrate was concentrated and dried under reduced pressure to obtain 95 g of SEPS-OH shown in Table 1 above.

[Synthesis Example 2 of Block Copolymer (b)] 70 g of isoprene obtained in Synthesis Example 1 was replaced by 70 g of a monomer mixture of isoprene and butadiene (isoprene / butadiene weight ratio 50/50). Then, a polymerization reaction, a molecular end modification reaction and a hydrogenation reaction were carried out to obtain 95 g of SEEPS-OH shown in Table 1.

[Synthesis Example 3 of Block Copolymer (b)] 260 ml of methylene chloride and methylcyclohexane 400 as a solvent were placed in a reactor equipped with a stirrer, which was replaced with nitrogen.
ml, titanium tetrachloride (Lewis acid) as a polymerization initiation system 4.
Charge 3 g and 0.33 g of 1,4-bis (1-methoxy-1-methylethyl) benzene, charge 80 g of isobutylene at −65 ° C., polymerize for 4 hours, then add 0.05 g of dimethylacetamide and 20 g of styrene. Polymerization was carried out at the same temperature for 4 hours. The reaction was stopped by adding 100 ml of methanol to the obtained reaction mixture. The obtained reaction mixture is subjected to decatalysis by washing it with a potassium hydroxide aqueous solution three times in a separating funnel, and then concentrated and dried under reduced pressure to bond chlorine atoms to both ends of the molecule. 100 g of a product containing the block copolymer as a main component was obtained. 100 g of this product and 1.0 g of potassium t-butoxide were dissolved in 600 ml of tetrahydrofuran and refluxed at 55 ° C. for 20 hours to carry out the dehydrochlorination reaction of the molecular end portion. After washing the obtained reaction mixture in a separating funnel,
By concentrating, 94 g of a block copolymer having carbon-carbon double bonds formed at both ends of the molecule was recovered.
The obtained block copolymer having a carbon-carbon double bond formed was dried and then distilled with tetrahydrofuran 60.
It was dissolved in 0 ml. While stirring this solution in a pressure vessel equipped with a stirrer under conditions of 0 ° C. and a nitrogen atmosphere, a 0.1 mol% tetrahydrofuran solution containing 0.6 g of a borane tetrahydrofuran complex was added dropwise to the solution to carry out the addition reaction. I went for 2 hours. After the addition reaction, bubbling nitrogen,
5 g of sodium hydroxide and a 30 wt% hydrogen peroxide aqueous solution (hydrogen peroxide content: 0.5 g) were added, and a substitution reaction was carried out at 30 ° C. for 2 hours. Then, the obtained reaction mixture was washed in a separating funnel and the solvent was distilled off to obtain 88 g of HO-SiBuS-OH shown in Table 1.

[Synthesis Example 1 of Block Copolymer Different from Block Copolymer (b)] Synthesis Example 1 of Block Copolymer
After the polymerization was carried out in the same manner as in, the reaction was stopped by adding methanol as it was without adding ethylene oxide as the end modifier. Then, a hydrogenation reaction was carried out in the same manner as in Synthesis Example 1, and SE shown in Table 1 was used.
98 g of PS was obtained.

[Example 1] After washing with acetone, sufficiently dried paraformaldehyde was pyrolyzed at 160 ° C, and the generated formaldehyde gas was passed through a U-shaped tube and trapped twice at -19 ° C. did. Cyclohexane 5
In 100 g, an amount of 0.1 mmol / l of dibutyltin dilaurate as an initiator, which was sufficiently dried, was obtained.
90 g of S-OH (as shown in Table 1 above) and 14.6 mmol / l of hexanol as molecular weight regulator.
Was dissolved. The obtained solution was dissolved in 1500 g of cyclohexane so that 300 g of the above-mentioned formaldehyde, dibutyltin dilaurate as an initiator and hexanol as a molecular weight regulator were 0.1 mmol / l and 16.0 mmol / l, respectively. The cyclohexane solution thus obtained was fed in parallel for 3 hours. During this period, the reaction temperature was maintained at 50 ° C. The reaction mixture obtained by carrying out the polymerization reaction in this way is filtered, and the obtained solid is thoroughly washed with acetone,
By vacuum drying at 60 ° C., 360 g of a white powdery polyacetal polymer composition was obtained. Various test pieces were prepared by press-molding the obtained polyacetal polymer composition according to the above method.

[Second Embodiment] In the first embodiment, the SEPS
SEEPS-O shown in Table 1 instead of 90 g of -OH
361 g of a polyacetal polymer composition was obtained in the same manner except that 90 g of H was used. Various test pieces were prepared by press-molding the obtained polyacetal polymer composition according to the above method.

[Embodiment 3] In the first embodiment, the SEPS
OH-SiBu shown in Table 1 instead of 90 g of -OH
313 g of a polyacetal polymer composition was obtained in the same manner except that 45 g of S-OH was used. Various test pieces were prepared by press-molding the obtained polyacetal polymer composition according to the above method.

COMPARATIVE EXAMPLE 1 In Example 1, the amount of dibutyltin dilaurate to be 0.1 mmol / l, SE
16. Instead of the cyclohexane solution obtained by dissolving 90 g of PS-OH and 14.6 mmol / l of hexanol in 500 g of cyclohexane, an amount of 0.1 mmol / l of dibutyltin dilaurate and 16. 278 g of a polyacetal-based polymer (polyoxymethylene) was obtained by carrying out the polymerization reaction and the post-treatment in the same manner except that the cyclohexane solution obtained by dissolving 0 g / l in 500 g of cyclohexane was used. . Various test pieces were prepared by press-molding the obtained polyacetal polymer according to the above method.

[Comparative Example 2] In Example 1, SEPS
90% of SEPS shown in Table 1 instead of 90 g of -OH
355 g of a polyacetal polymer composition was obtained in the same manner except that g was added. Various test pieces were prepared by press-molding the obtained polyacetal polymer composition according to the above method.

Table 2 below shows the results of various measurements on the test pieces obtained in the above Examples and Comparative Examples.

[0053]

[Table 2]

From the results shown in Table 2 above, the polyacetal polymer compositions according to the present invention of Examples 1 to 3 are the polyacetal polymer compositions of Comparative Example 1 alone and the polyacetal polymer compositions of Comparative Example 2 other than the present invention. It can be seen that it gives a molded product having a large tensile elongation and a high impact resistance as compared with the product. Further, it can be seen that the polyacetal polymer compositions according to the present invention of Examples 1 to 3 give molded products which are lighter than the polyacetal polymer compositions of Comparative Example 1 alone.

[0055]

INDUSTRIAL APPLICABILITY The polyacetal polymer composition of the present invention has improved impact resistance and elongation in a molded article and reduced specific gravity, as compared with the polyacetal polymer alone. Therefore, the polymer composition is extremely useful in practice as a raw material for various molded articles.

Claims (2)

[Claims] 1. When polymerizing formaldehyde (a) to produce a polyacetal polymer, an aromatic vinyl compound polymer block and 1,
2-one or more of at least one block (A) selected from the group consisting of hydrogenated polybutadiene blocks in which polybutadiene having a bonding amount of less than 30% is hydrogenated,
Hydrogenated polyisoprene block, 1,2-bond content 30 ~
Hydrogenated polybutadiene block in the form of 80% polybutadiene hydrogenated and hydrogenated isoprene in the form of hydrogenated isoprene / butadiene random copolymer /
Or at least one block (B) selected from the group consisting of butadiene copolymer blocks, or at least one aromatic vinyl compound polymer block (C) and a polyisobutylene block ( A block copolymer (b) containing at least one of D) and having a hydroxyl group at the terminal, in which the weight ratio of formaldehyde (a) to block copolymer (b) is (a) / (b). Four
A polyacetal polymer composition obtained by adding at a ratio within a range of 0/60 to 98/2. 2. A molded article comprising the polyacetal polymer composition according to claim 1.