JP2001240639A - Modified polyacetal resin and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modified polyacetal resin giving a thin-walled molded body excellent in surface appearance and at the same time having shock resistance. SOLUTION: This modified polyacetal resin is mainly composed of an oxymethylene unit and comprises a recurring unit of formula [I] (wherein, R1 is a 1-20C alkylene or alkylidene, and when m is larger than 1, the groups R1 may be identical to or different from each other; R2 is a group selected from a 1-20C alkyl, a 2-20C alkenyl, a 2-20C alkynyl, phenyl, a 1-20C alkyl- substituted phenyl, a 1-20C alkylidene-substituted phenyl, naphthyl, a 1-20C alkyl-substituted naphthyl, a 1-20C alkylidene-substituted naphthyl, biphenyl and cumylphenyl; m is 0-20; and q is an average recurring number of a block unit, and it is 2-1,000).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a modified polyacetal resin, and more particularly to a modified polyacetal resin having excellent impact resistance and a method for producing the same.

[0002]

2. Description of the Related Art Polyacetal resins are well-balanced in mechanical properties, chemical resistance, slidability, etc., and are easy to process. Widely used mainly for various mechanical parts.

[0003] In recent years, as the range of use has been expanded, polyacetal resins are often used for thin parts. Although the polyacetal resin has relatively good fluidity and moldability, the surface of the molded article may be rough due to poor flow to the thin part and poor filling at the end of the cavity. Defects can significantly reduce their commercial value, and often require careful examination of molding conditions. On the other hand, as a countermeasure against polymerization, a proposal has been made to increase the melt index of the resin itself by increasing the molecular weight regulator during the polymerization of the polyacetal resin. However, such a method results in a decrease in mechanical properties, particularly a decrease in impact resistance, so that a favorable result cannot be obtained, and further improvement is required.

Japanese Patent Application Laid-Open No. 4-339831 proposes forming a branch in a polyacetal resin by using a polyfunctional glycidyl compound (diglycidyl ether compound). In this method, although the fluidity of the resin is improved, surface roughness considered to be derived from the branched component occurs,
Further, the improvement of the impact resistance is small, which is not preferable. On the other hand, as a measure against the polyacetal resin composition, Japanese Patent Publication No.
JP-A-39182 and JP-A-9-40842 propose a composition obtained by melt-blending a polyacetal resin having two or more components and different melt indices. However, such a method requires the preparation of various types of polyacetal resins, which complicates the process, and is unsuitable in terms of quality and cost. As described above, it is difficult to produce a polyacetal resin which is excellent in the surface appearance of a thin-walled molded product and also has impact resistance, and there is an urgent need for improvement.

[0005]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a modified polyacetal resin which is excellent in the surface appearance of a thin-walled molded product and has an impact resistance.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that the above-mentioned problems can be solved by using a modified polyacetal resin having a specific chemical structure. Thus, the present invention has been completed. That is, a first aspect of the present invention provides a modified polyacetal resin having an oxymethylene unit as a main unit and containing a repeating unit represented by the following formula [1].

[0007]

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(Provided that R ¹ is an alkylene group having 1 to 20 carbon atoms or an alkylidene group, and when m is greater than 1,
¹ may be the same or different. R ² has 1 to 1 carbon atoms
20, an alkyl group having 20 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a phenyl group, an alkyl (1 to 20 carbon atoms) substituted phenyl group, an alkylidene (1 to 20 carbon atoms) substituted phenyl group, A group selected from a naphthyl group, an alkyl (C1-20) substituted naphthyl group, an alkylidene (C1-20) substituted naphthyl group, a biphenyl group and a cumylphenyl group. m is 0-20. q is the average number of repetitions per block, which is 2 to 1,000. A second aspect of the present invention is that the modified polyacetal resin comprises (A) trioxane, (B) a cyclic ether and / or cyclic formal, and (C) a monofunctional glycidyl ether compound represented by the following formula [2]: The modified polyacetal resin according to the first aspect of the present invention is characterized by being polymerized using a cationic polymerization catalyst.

[0009]

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(Provided that R ¹ is an alkylene group having 1 to 20 carbon atoms or an alkylidene group, and when m is greater than 1,
¹ may be the same or different. R ² has 1 to 1 carbon atoms
20 alkyl groups, alkenyl groups having 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms, phenyl groups, phenyl groups substituted with alkyl (1 to 20 carbon atoms), phenyl groups substituted with alkylidene (1 to 20 carbon atoms), A group selected from a naphthyl group, an alkyl (C1-20) substituted naphthyl group, an alkylidene (C1-20) substituted naphthyl group, a biphenyl group and a cumylphenyl group. m is 0-20. A third aspect of the present invention is that (B) the cyclic ether and / or cyclic formal is ethylene oxide, 1,3-dioxolan,
The modified polyacetal resin according to the first or second aspect of the present invention, which is at least one member selected from the group consisting of diethylene glycol formal and 1,4-butanediol formal. A fourth aspect of the present invention is the first aspect, wherein the cationic polymerization catalyst (D) is at least one member selected from the group consisting of boron trifluoride and a boron trifluoride coordination compound.
3. A modified polyacetal resin according to any one of items 1 to 3. A fifth aspect of the present invention is any one of the first to fourth aspects of the present invention.
The modified polyacetal resin described in the above item (A) is obtained by mixing (A) 100 parts by weight of trioxane, (B) 0.1 to 20 parts by weight of a cyclic ether and / or cyclic formal, and (C) a monofunctional glycidyl ether compound represented by the following formula [2]: 0.001
20 parts by weight of (D) a bulk polymerization using a cationic polymerization catalyst to produce a modified polyacetal resin,
A mixture obtained by once mixing (C) a monofunctional glycidyl ether compound and (D) a cationic polymerization catalyst is added to (A) trioxane, or (A) trioxane and (B) cyclic ether and / or cyclic formal, and supplied and polymerized. To provide a method for producing a modified polyacetal resin.

[0011]

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(Provided that R ¹ is an alkylene group having 1 to 20 carbon atoms or an alkylidene group, and when m is greater than 1,
¹ may be the same or different. R ² has 1 to 1 carbon atoms
20 alkyl groups, alkenyl groups having 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms, phenyl groups, phenyl groups substituted with alkyl (1 to 20 carbon atoms), phenyl groups substituted with alkylidene (1 to 20 carbon atoms), A group selected from a naphthyl group, an alkyl (C1-20) substituted naphthyl group, an alkylidene (C1-20) substituted naphthyl group, a biphenyl group and a cumylphenyl group. m is 0-20. )

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The characteristic feature of the modified polyacetal resin of the present invention is that it has an oxymethylene unit as a main unit and contains a repeating unit of the monomer of the above formula [2]. To be contained. The average repeating number q of the repeating unit of the above formula [1] is 2 to 1,000, preferably 10 to 1,0.
00. It is presumed that the block structure formed of the repeating units effectively functions to achieve both excellent surface appearance and impact resistance of the thin-walled molded product. Further, the content of the repeating unit of the formula [1] in the modified polyacetal resin is the same as the range calculated from the reaction ratio of the (C) monofunctional glycidyl ether compound to trioxane described below. The average repetition number q of the block unit [1] in the modified polyacetal resin can be quantified by subjecting the resin to thermal decomposition with a mixed solution of hydrochloric acid / methanol and then measuring the molecular weight of the residue. This is because the block unit has a chemically stable repeating unit, C—C—O—, and thus remains unbroken even after acid treatment.
This is because the chemically quasi-unstable oxymethylene unit C—O— undergoes acid decomposition and can be separated. As a means of analyzing the molecular weight in block units, a conventionally known analysis method is applied, and for example, gel permeation chromatography (GPC), gas chromatography (GC), liquid chromatography (LC), mass spectrometry (LC) MS) and the like. In addition, a specific measurement example will be described later in an example.

In the modified polyacetal resin of the present invention, in order to obtain a polyacetal structure having an oxymethylene unit as a main unit, trioxane,
Although it is necessary to use formalin or the like as a main raw material, it is particularly preferable to use trioxane. In order to further improve the thermal stability of the resin, it is preferable to use a cyclic ether and / or a cyclic formal in combination to form a so-called copolymer type polyacetal.

The modified polyacetal resin of the present invention can be obtained by taking the above-mentioned requirements into consideration. In particular, to a limited extent, the modified polyacetal resin of the present invention comprises:
A modified polyacetal resin obtained by polymerizing (A) trioxane and (B) a cyclic ether and / or cyclic formal, and (C) a monofunctional glycidyl ether compound represented by the formula [2] using (D) a cationic polymerization catalyst. And
The molecular weight, melt viscosity and the like of the resin are not particularly limited as long as the resin can be melt-molded. However, particularly preferred is a number average molecular weight of 20,000 to 400,000 or a melt index (according to ASTM D-1238). , 190 ° C)
It is 0.01 to 100 g / 10 min.

The (A) trioxane used in the present invention is:
It is a cyclic trimer of formaldehyde, generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst, and purified by a method such as distillation and used.

Examples of the cyclic ether and / or cyclic formal (B) used in the present invention include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, styrene oxide,
Oxetane, 3,3-bis (chloromethyl) oxetane, tetrahydrofuran, trioxepane, 1,3-dioxolan, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5- Pentanediol formal, 1,6-hexanediol formal and the like, among which ethylene oxide, 1,3-dioxolan, diethylene glycol formal, 1,4-
Butanediol formal is preferred. The amount of the cyclic ether and / or cyclic formal used is preferably 0.1 to 20 parts by weight in total of one or two or more kinds based on 100 parts by weight of trioxane in consideration of the rigidity and chemical resistance of the molded article. And particularly preferably 0.3 to 15 parts by weight.

The monofunctional glycidyl ether compound (C) used in the present invention is exemplified by the compound represented by the above formula [2]. Specific compounds include methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, n-butyl glycidyl ether,
Octyl glycidyl ether, 2-ethylhexyl glycidyl ether, decyl glycidyl ether, dodecyl glycidyl ether, stearyl glycidyl ether,
Ethoxybutyl glycidyl ether, 1-allyloxy-2,3-epoxypropane, 1- (1 ′, 1′-dimethylpropargyloxy) -2,3-epoxypropane, phenylglycidylether, cresylglycidylether, butylphenylglycidylether , Naphthyl glycidyl ether, phenylphenol glycidyl ether, benzyl alcohol glycidyl ether and the like.

(C) per 100 parts by weight of trioxane
One to two or more monofunctional glycidyl ether compounds are used in an amount of 0.001 to 20 parts by weight, particularly preferably 0.1 to 20 parts by weight.
01 to 10 parts by weight. If the amount is less than 0.001 part by weight, it is difficult to obtain both of moldability, impact resistance, and surface characteristics. The chemical resistance and the like are lowered, and both are not preferred. Further, the monofunctional glycidyl ether compound (C) may be used after previously diluted with another organic solvent or the like.

The (D) cationic polymerization catalyst used in the present invention includes lead tetrachloride, tin tetrachloride, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony trichloride, phosphorus pentafluoride, pentafluoride, Antimony fluoride, boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetic anhydride, boron trifluoride triethylamine complex compound, etc. Boron trifluoride coordination compound, perchloric acid, acetyl perchlorate, t-butyl perchlorate, hydroxyacetic acid,
Inorganic and organic acids such as trichloroacetic acid, trifluoroacetic acid, p-toluenesulfonic acid, etc .; One or more of compounds, alkyl metal salts such as diethylzinc, triethylaluminum, diethylaluminum chloride and the like, heteropolyacids, isopolyacids and the like can be mentioned. Among them, in particular, the reactivity of the block unit, the polymerizability of polyacetal, the reactivity, and in terms of deactivation of the catalyst, Lewis acid-based catalyst, particularly, boron trifluoride, boron trifluoride diethyl etherate, Boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetic unhydrate,
Boron trifluoride coordination compounds such as boron trifluoride triethylamine complex compounds are preferred. These (D) cationic polymerization catalysts may be used as they are or may be diluted in advance with an organic solvent or the like, and the preparation method is not particularly limited.

In addition to the above components, a component for adjusting the molecular weight can be used in combination. Examples of the molecular weight regulator used here include low molecular weight acetal compounds having an alkoxy group, alcohols such as methanol, ethanol, and butanol, water, and ester compounds. Among them, a low molecular weight acetal compound having an alkoxy group is preferable, and specific compound names include methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal, and oxymethylene di-n-butyl ether. The amount or method of adding these molecular weight modifiers is not particularly limited as long as the effects of the present invention are not impaired.

Next, a production method for obtaining the modified polyacetal resin of the present invention will be described. The production of the modified polyacetal resin of the present invention may be performed by the above-mentioned (A) trioxane, (B) cyclic ether and / or cyclic formal,
(C) a monofunctional glycidyl ether compound, and (D)
It is carried out by polymerization mainly using a cationic polymerization catalyst. The polymerization is not particularly limited by the apparatus, a known apparatus is used, and any method such as a batch system, a semi-batch system, and a continuous system can be used. The polymerization temperature is 65
It is preferable to keep the temperature at 135 ° C.

Here, the following method is exemplified as a polymerization method for obtaining the modified polyacetal resin of the present invention. A mixture obtained by once mixing (I) the (C) monofunctional glycidyl ether compound and (D) the cationic polymerization catalyst,
A method of performing polymerization by adding and supplying (A) trioxane or (A) trioxane and (B) cyclic ether and / or cyclic formal. (II) After polymerizing (A) trioxane or (A) trioxane and (B) cyclic ether and / or cyclic formal using (D) cationic polymerization catalyst, (C) monofunctional glycidyl ether compound is added and supplied. To carry out further polymerization. (III) After polymerizing (A) trioxane or (A) trioxane and (B) cyclic ether and / or cyclic formal using (D) cationic polymerization catalyst, (C) monofunctional glycidyl ether compound and (D) A) a method in which a mixture once mixed with a cationic polymerization catalyst is added and supplied to carry out polymerization. (IV) After polymerization according to the above (I) to (III), (A)
A method in which at least one selected from the group consisting of trioxane, (B) a cyclic ether and / or cyclic formal, and (C) a monofunctional glycidyl ether compound is added and supplied at least once to carry out polymerization. Among them, (I)
The mixture obtained by once mixing (C) the monofunctional glycidyl ether compound and (D) the cationic polymerization catalyst is added to (A) trioxane or (A) trioxane and (B) cyclic ether and / or cyclic formal to be polymerized. Is preferred.

In mixing the above (C) monofunctional glycidyl ether compound and (D) cationic polymerization catalyst, the method of mixing the components is not limited at all. For example, two consecutive
A method in which components are combined and mixed in a pipe, a method in which two components are continuously combined and further mixed using a static mixer, a method in which a mixed component in which two components are mixed once in a vessel equipped with a stirrer, and the like are supplied. .

In the mixing of the above components, the mixing temperature and mixing time depend on (C) the amount of the monofunctional glycidyl ether compound used, and (D) the amount of the cationic polymerization catalyst depends on various conditions. Although not particularly limited, if specified, a preferable mixing temperature is from -70 to 150 ° C, particularly preferably from -50 to 100 ° C, and a preferable mixing time is from 0.1 second to 20 hours. 5 seconds to 10 hours are preferred. In addition, in mixing the above components, the above-mentioned molecular weight regulator can be used in combination.

Incidentally, a method for producing a polyacetal resin using a glycidyl ether compound is disclosed in
Japanese Patent Application Publication No. 1-35649 proposes a method in which a mixture of a cyclic ether and / or cyclic formal, a polyfunctional glycidyl ether compound, and a cationic polymerization catalyst is once added to trioxane and supplied to the trioxane. Since a plurality of glycidyl ether compounds are bonded in a network and a complex reaction with a cyclic ether and / or cyclic formal occurs, the glycidyl ether compound chemically forms a heterogeneous structure with the block unit defined in the present invention. In such a case, it is difficult to produce the modified polyacetal resin having the chemical structure of the present invention, and formation of a gel-like substance is also observed as described later in Examples and Comparative Examples. Further, no improvement is observed in both the impact resistance and the surface appearance, which is not preferable.

Deactivation by neutralization of the catalyst after polymerization can be achieved by adding a basic compound or an aqueous solution thereof to the reaction product discharged from the polymerization machine after the polymerization reaction or the reaction product in the polymerization machine. Do it. Examples of the basic compound for neutralizing and deactivating the polymerization catalyst include ammonia; amines such as triethylamine, tributylamine, triethanolamine and tributanolamine; hydroxide salts of alkali metals and alkaline earth metals; Other known catalyst deactivators are used. After the polymerization reaction, it is preferable to add these aqueous solutions to the product promptly to deactivate the product.

After the polymerization method and the deactivation method, if necessary, washing, separation and recovery of unreacted monomers, drying, etc. are performed by a conventionally known method. Further, if necessary, a stabilizing treatment is carried out by a known method such as decomposition removal of an unstable terminal or sealing of an unstable terminal with a stable substance, and various necessary stabilizers are blended. As the stabilizer used here,
Any one or more of a hindered phenol compound, a nitrogen-containing compound, an alkali or alkaline earth metal hydroxide, an inorganic salt, a carboxylate and the like can be mentioned. Furthermore, as long as the present invention is not impaired, if necessary, general additives for thermoplastic resins, for example, dyes, coloring agents such as pigments, lubricants, nucleating agents, release agents, antistatic agents, surfactants, One or more kinds of organic polymer materials, inorganic or organic fibrous, powdery, and plate-like fillers can be added.

[0029]

EXAMPLES Hereinafter, the present invention will be described specifically, but the present invention is not limited to these examples. The method used for the characteristic evaluation in the examples is as follows. 1) Melt index Measurement was performed at 190 ° C. according to ASTM D-1238. 2) Measurement of average repetition number (q) of block unit The modified polyacetal resin was heated and decomposed in a mixed solution of hydrochloric acid and methanol, the decomposed liquid was neutralized, and after separation and purification, the decomposition residue was analyzed as follows. Method for measuring number average molecular weight: (i) Component having a long average number of repetitions q A polystyrene gel is used for a separation column, and hexafluoroisopropanol is used as a carrier (carrier flow is 0.1%).
2. ml / min), column oven temperature 40 ° C,
The sample solution concentration was 0.1 wt%, and the refractive index (RI) and light scattering (LS) were used as detectors. The average number of repetitions (q) per block is calculated by calculating the number average molecular weight of the block unit in terms of polymethyl methacrylate having a known molecular weight from the GPC peak of the decomposition product, and then using the number average molecular weight as the It was calculated by dividing by the molecular weight of the functional glycidyl ether compound. (Ii) A component having a short average number of repetitions q In the case where the block unit has a low molecular weight that cannot be measured by GPC, measurement was performed by gas chromatography (GC). The sample was treated in the same manner as above, and 50 mg of the separated and purified decomposition residue was dissolved in 1 ml of methanol, sampled in a microvial (200 μl), and used for GC analysis. The GC measurement was performed using a slightly polar column DB5 (30 m) manufactured by J & W Co.
After holding for 5 minutes, the temperature was raised to 250 ° C. at 5 ° C./min,
The temperature was maintained for 1 minute. Using a FID for the detector, based on the hydrate of the monofunctional glycidyl ether compound used, estimating the next peak as a dimer hydrate of the above compound, and estimating the following oligomer peak, Assuming that the area sensitivity of each peak was the same, the number average molecular weight was determined. The average number of repetitions (q) per block was calculated by dividing the number average molecular weight by the molecular weight of the monofunctional glycidyl ether compound used. 3) Measurement of number average molecular weight (Mn) of modified polyacetal resin GPC measurement was performed under the same conditions as in (i) of 2), and the number average molecular weight was calculated in terms of polymethyl methacrylate having a known molecular weight. 4) Evaluation of appearance of thin-walled molded product Using a Nikko J75SS2A (φ35) as an injection molding machine, a thin test piece of 70 (mm) × 70 (mm) × 0.5 (mm) was injection-molded (cylinder). (Temperature: 200 ° C., mold temperature: 90 ° C.), the surface roughness of the molding surface, and defective filling at the end of the cavity were visually evaluated. The evaluation results were ranked as good, moderately good, and bad. 5) Impact resistance evaluation Using an injection molding machine similar to a thin molded product, 13 (mm)
A test piece of × 65 (mm) × 6 (mm) is injection-molded (cylinder temperature 200 ° C., mold temperature 80 ° C.), and ASTM
An Izod test (no notch) was performed according to D-256.

(Example 1) A continuous mixing reactor having a jacket through which a heat (cooling) medium passes and having a cross section having a shape in which two circles partially overlap with each other, and a rotary shaft with paddles ( Using a polymerization machine), while rotating each of the two rotating shafts with paddles at 150 rpm, at one end, 3.3 parts by weight of 1,3-dioxolane, 0.1 part by weight of methylal as a molecular weight regulator, and Trioxane 10
0 parts by weight of the mixture were continuously fed. Subsequently, after supplying all of the above, 2.5 parts by weight of n-butyl glycidyl ether (where R ² is an n-butyl group and m is 0 in the formula [2]) and boron trifluoride di-n- Butyl etherate 0.0
One part by weight was mixed and mixed in a pipe, and bulk polymerization was performed while continuously supplying the mixture from another supply port of the polymerization machine. The reaction product discharged from the outlet of the polymerization machine is immediately passed through a crusher,
The solution was added to an aqueous solution containing 5% by weight at 60 ° C., pulverized into particles, and simultaneously deactivated the catalyst. Further, after separation, washing and drying, a crude polyacetal resin was obtained. Then, pentaerythrityl-tetrakis [3- (3,5-di-t) was used as a stabilizer with respect to 100 parts by weight of the crude polyacetal resin.
ert-butyl-4-hydroxyphenyl) propionate] (Irganox 1010, manufactured by Ciba-Geigy)
0.3 parts by weight and 0.15 parts by weight of melamine are added,
After mixing with a Henschel mixer, vented 2
The mixture was melt-kneaded at 200 ° C. in a screw extruder to obtain a stabilized polyacetal resin (melt index: 8.8 g / 10 min, Mn 69,000) at the same time as stabilization. The obtained resin was heated and decomposed with a mixed solution of hydrochloric acid and methanol, and then the residue was measured for molecular weight using GPC. As a result, the average number of repetitions per block (q)
Was 51.1. The obtained resin has good appearance of thin-walled molded product (surface roughness of molding surface, filling of cavity end), and Izod impact strength (no notch)
Showed a good value of 821 J / m. The results are shown in Table 1 (in Table 1, the butyl group is an n-butyl group, the same applies hereinafter).

Example 2 Instead of n-butyl glycidyl ether, R ¹ is an ethylene group, R ² is an n-butyl group,
Polymerization and post-treatment were conducted in the same manner as in Example 1 except that 3.2 parts by weight of glycidyl ether having m of 1 was used, and a pellet-shaped modified polyacetal resin (melt index: 8.6 g)
/ 10 min, Mn 69,500). The resulting resin was subjected to thermal decomposition with a mixed solution of hydrochloric acid and methanol, and the residue was measured for molecular weight using GPC. as a result,
The average number of repetitions (q) per block was 45.0. The obtained resin had a good appearance of a thin molded article (surface roughness of the molding surface, filling of the cavity end), and a high Izod impact strength (no notch) of 832 J / m. Table 1 shows the results.

Example 3 Same as Example 1 except that 2.8 parts by weight of glycidyl ether having R ¹ as an ethylene group, R ² as an ethyl group and m as 2 was used instead of n-butyl glycidyl ether. After polymerization and post-treatment, the pelletized modified polyacetal resin (melt index 9.3 g / 10
min, Mn 66,500). The obtained resin is
After decomposing the resin by heating with a mixed solution of hydrochloric acid and methanol, the residue was measured for molecular weight using GPC. As a result, the average number of repetitions (q) per block was 47.1. The obtained resin had a good appearance of a thin molded product (molded surface roughness, filling of the cavity end), and an Izod impact strength (without notch) of 793 J / m. . Table 1 shows the results.

Example 4 Polymerization and treatment were carried out in the same manner as in Example 1 except that 2.5 parts by weight of ethylene oxide was used instead of 1,3-dioxolane, and a modified polyacetal resin in the form of pellets (melt index 8. 6g / 10mi
n, Mn 69,000). The resulting resin was subjected to thermal decomposition with a mixed solution of hydrochloric acid and methanol, and the residue was measured for molecular weight using GPC. As a result, the average number of repetitions (q) per block was 39.0. The obtained resin has a good appearance of a thin molded product (roughness of the molding surface, filling of the cavity end), and an Izod impact strength (no notch) of 782 J / m. Indicated. Table 1 shows the results.

Example 5 The same procedure as in Example 1 was carried out except that the amount of n-butyl glycidyl ether was changed to 0.5 part by weight, and a pelletized modified polyacetal resin (melt index 8.5 g / 10 min, Mn 69,00
0) was obtained. The obtained resin has a slightly good surface roughness on the molding surface and a good filling at the cavity end, and an Izod impact strength (without notch) of 753 J / m. It showed good values. Table 1 shows the results.

(Comparative Example 1) A continuous mixing reactor was used in the same manner as in Example 1, and 1,3-dioxolane was added to one end of the reactor.
3 parts by weight, n-butyl glycidyl ether (R ² is n-butyl
A mixture of butyl group, m: 0) 2.5 parts by weight, methylal 0.1 part by weight, and trioxane 100 parts by weight was continuously supplied. Subsequently, after supplying all of the above, bulk polymerization was performed while continuously supplying 0.01 part by weight of boron trifluoride dibutyl etherate to the polymerization machine. The reaction product discharged from the polymerization machine outlet was treated in the same manner as in Example 1,
A pellet-like polyacetal resin (melt index 8.6 g / 10 min, Mn 69,000) was obtained. The resulting resin was decomposed by heating with a mixed solution of hydrochloric acid and methanol, and the residue was measured for molecular weight using GPC, but could not be measured. Furthermore, as a result of GC measurement, the average number of repetitions (q) per block was 1.1. The obtained resin is poor in the appearance of a thin molded product (molded surface is rough, filling in the end of the cavity), and the Izod impact strength (without notch) is a slightly lower value of 622 J / m. Was. Table 1 shows the results.

(Comparative Example 2) A continuous mixing reactor was used in the same manner as in Example 1, and 2.5 parts by weight of n-butyl glycidyl ether (R ² was an n-butyl group, m was 0) A mixture of 0.1 part by weight of methylal and 100 parts by weight of trioxane was continuously supplied. Then, at the same time,
3.3 parts by weight of dioxolane and 0.01 part by weight of boron trifluoride di-n-butyl etherate are mixed and mixed in a pipe, and the mixture is continuously supplied from another supply port of the polymerization machine to form a lump. Polymerization was performed. The reaction product discharged from the outlet of the polymerization machine was treated in the same manner as in Example 1 and pelletized polyacetal resin (melt index 8.5 g /
10 min, Mn 70,500). The resulting resin was decomposed by heating with a mixed solution of hydrochloric acid and methanol, and the residue was measured for molecular weight using GPC, but could not be measured. Furthermore, as a result of GC measurement, the average number of repetitions (q) per floc unit was 1.2. The obtained resin is
The appearance of the thin molded product (roughness of the molded surface, filling of the cavity end) was poor, and the Izod impact strength (without notch) was a slightly lower value of 650 J / m. Table 1 shows the results.

COMPARATIVE EXAMPLE 3 A continuous mixing reactor was used in the same manner as in Example 1, and 1,3-dioxolane was added to one end of the reactor.
A mixture of 3 parts by weight, 0.1 part by weight of methylal, and 100 parts by weight of trioxane was continuously supplied. Subsequently, simultaneously with boron trifluoride di-n-butyl etherate 0.01
Bulk polymerization was performed while continuously supplying parts by weight to the polymerization machine. The reaction product discharged from the outlet of the polymerization machine was treated in the same manner as in Example 1 to obtain a pelletized polyacetal resin (melt index 8.7 g / 10 min, Mn6
9,500). The obtained resin had poor appearance of a thin-walled molded product (roughened molding surface, filling at the end of the cavity), and had an Izod impact strength (no notch) of 6
The value was slightly lower at 31 J / m. Further, the chemical structure of the starting compound is obviously different from the chemical structure of the starting compound according to the present invention, and the obtained resin is different from the chemical structure of the present invention. Table 1 shows the results.

Comparative Example 4 A continuous mixing reactor was used in the same manner as in Example 1, and 1,3-dioxolane was added to one end of the reactor.
A mixture of 3 parts by weight, 0.2 part by weight of methylal, and 100 parts by weight of trioxane was continuously supplied. Subsequently, simultaneously with boron trifluoride di-n-butyl etherate 0.01
Bulk polymerization was performed while continuously supplying parts by weight to the polymerization machine. The reaction product discharged from the outlet of the polymerization machine was treated in the same manner as in Example 1 to obtain a pelletized polyacetal resin (melt index: 29.2 g / 10 min, Mn5
2,000). The resulting resin has a slightly good appearance (thin surface roughening, filling of cavity end) with a thin molded product, and Izod impact strength (no notch)
Showed a low value of 561 J / m. Further, the chemical structure of the starting compound is obviously different from the chemical structure of the starting compound according to the present invention, and the obtained resin is different from the chemical structure of the present invention. Table 1 shows the results.

COMPARATIVE EXAMPLE 5 A continuous mixing reactor was used in the same manner as in Example 1, and one end of
And, a mixture of 100 parts by weight of trioxane was continuously supplied. Then, after supplying the above, 3.3 parts by weight of 1,3-dioxolane, 0.23 parts by weight of 1,4-butanediol glycidyl ether, and boron trifluoride di-n
-Butyl etherate (0.01 part by weight) was combined and mixed in a pipe, and bulk polymerization was performed while continuously supplying the mixture from another supply port of the polymerization machine. The reaction product discharged from the polymerization machine outlet was treated in the same manner as in Example 1,
A pellet-like polyacetal resin (melt index: 21.0 g / 10 min) was obtained. The obtained resin was poor in the appearance of a thin molded product (filling into the end of the cavity), and was poor in the appearance of a thin molded product (molded surface roughness).
The Izod impact strength (without notch) is 579J
/ M and a lower value. Further, the obtained resin was heated and decomposed in a mixed solution of hydrochloric acid and methanol, and the decomposed liquid was neutralized and separated and purified. As a result, a gel insoluble in hexafluoroisopropanol was found. Further, the chemical structure of the starting compound is obviously different from the chemical structure of the starting compound according to the present invention, and the obtained resin is different from the chemical structure of the present invention. Table 1 shows the results.

[0040]

[Table 1]

[0041]

The modified polyacetal resin of the present invention is excellent in the surface appearance of a thin-walled molded product and can also have impact resistance.

Claims (5)

[Claims] 1. A modified polyacetal resin having an oxymethylene unit as a main unit and containing a repeating unit represented by the following formula [1]. Embedded image (However, R ¹ is an alkylene group or an alkylidene group having 1 to 20 carbon atoms, and when m is greater than ¹ , each R ¹ may be the same or different. R ² is an alkyl group having 1 to 20 carbon atoms. An alkenyl group having 2 to 20 carbon atoms and 2 to 2 carbon atoms
0 alkynyl group, phenyl group, alkyl (1 to
20) Substituted phenyl group, alkylidene (having 1-2 carbon atoms)
0) substituted phenyl group, naphthyl group, alkyl (C 1
~ 20) substituted naphthyl group, alkylidene (having 1 to 2 carbon atoms)
0) a group selected from a substituted naphthyl group, a biphenyl group and a cumylphenyl group. m is 0-20. q is the average number of repetitions per block, which is 2 to 1,000. ) 2. A modified polyacetal resin comprising (A) trioxane, (B) a cyclic ether and / or cyclic formal, and (C) a monofunctional glycidyl ether compound represented by the following formula [2]: (D) a cationic polymerization catalyst The modified polyacetal resin according to claim 1, wherein the modified polyacetal resin is polymerized by using. Embedded image (However, R ¹ is an alkylene group or an alkylidene group having 1 to 20 carbon atoms, and when m is greater than ¹ , each R ¹ may be the same or different. R ² is an alkyl group having 1 to 20 carbon atoms. An alkenyl group having 2 to 20 carbon atoms and 2 to 2 carbon atoms
0 alkynyl group, phenyl group, alkyl (1 to
20) Substituted phenyl group, alkylidene (having 1-2 carbon atoms)
0) substituted phenyl group, naphthyl group, alkyl (having 1 carbon atom)
~ 20) substituted naphthyl group, alkylidene (having 1 to 2 carbon atoms)
0) a group selected from a substituted naphthyl group, a biphenyl group and a cumylphenyl group. m is 0-20. ) 3. The method according to claim 1, wherein (B) the cyclic ether and / or cyclic formal is at least one selected from the group consisting of ethylene oxide, 1,3-dioxolan, diethylene glycol formal, and 1,4-butanediol formal. 3. The modified polyacetal resin described in 1. above. 4. The modified polyacetal resin according to claim 1, wherein (D) the cationic polymerization catalyst is at least one selected from the group consisting of boron trifluoride and a boron trifluoride coordination compound. 5. The modified polyacetal resin according to claim 1, wherein (A) 100 parts by weight of trioxane and (B) a cyclic ether and / or cyclic formal.
1 to 20 parts by weight and (C) 0.001 to 20 parts by weight of a monofunctional glycidyl ether compound represented by the following formula [2] are bulk-polymerized using a (D) cationic polymerization catalyst to produce a modified polyacetal resin. At this time, a mixture obtained by once mixing (C) the monofunctional glycidyl ether compound and (D) the cationic polymerization catalyst is added to (A) trioxane, or (A) trioxane and (B) cyclic ether and / or cyclic formal, and supplied. And producing a modified polyacetal resin. Embedded image (However, R ¹ is an alkylene group or an alkylidene group having 1 to 20 carbon atoms, and when m is greater than ¹ , each R ¹ may be the same or different. R ² is an alkyl group having 1 to 20 carbon atoms. An alkenyl group having 2 to 20 carbon atoms and 2 to 2 carbon atoms
0 alkynyl group, phenyl group, alkyl (1 to
20) Substituted phenyl group, alkylidene (having 1-2 carbon atoms)
0) substituted phenyl group, naphthyl group, alkyl (having 1 carbon atom)
~ 20) substituted naphthyl group, alkylidene (having 1 to 2 carbon atoms)
0) a group selected from a substituted naphthyl group, a biphenyl group and a cumylphenyl group. m is 0-20. )