KR20140087671A - Polyoxymethylene Resins Composition - Google Patents

Abstract

The present invention relates to a polyoxymethylene resin composition and, more specifically, to a polyoxymethylene resin composition which comprises: a polyoxymethylene copolymer obtained by copolymerizing trioxane and oxyethylene compounds; and 0.01-0.5 parts by weight of a polyoxymethylene terpolymer obtained by copolymerizing trioxane, oxyethylene compounds and glycidyl compounds based on 100 parts by weight of the polyoxymethylene copolymer, and improves rigidity, creep resistance and crystalline properties.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyoxymethylene resin composition,

The present invention relates to a polyoxymethylene resin composition which can be used as engineering plastics.

The polyoxymethylene resin is a crystalline engineering plastic having excellent mechanical properties (rigidity, abrasion resistance, creep resistance, chemical resistance, dimensional stability) and high crystallinity. In recent years, as the use of such polyoxymethylene resin has been variously expanded, a resin composition having improved properties of a resin as a material thereof has been required and produced. Particularly, in consideration of excellent chemical resistance, rigidity and creep resistance of polyoxymethylene, there is used as an actual structural component of a fuel component and a door module portion. Such a molded product is continuously subjected to stress, Thereby causing creep destruction. In addition, there is a problem that breakage and wear of the component-bonded portion are determined by the difference in the shrinkage ratio generated after molding. Therefore, a polyoxymethylene resin composition having good rigidity and creep resistance and having a low shrinkage ratio after molding is strongly desired.

As a general method, inorganic fillers such as glass fiber and talc, wollastonite, and carbon fiber are mixed to improve the performance, as in the case of other engineering plastics such as polyamide and polybutylene terephthalate. However, In the case of the oxymethylene resin, the inorganic filler as described above is effective for improving the mechanical properties of stiffness and strength, but may not be an effective method because it may remarkably reduce creep resistance, durability and toughness . Further, when a large amount of inorganic filler is added, the thermal stability of the polyoxymethylene resin is lowered and the moldability and the like may be adversely affected, so that the conventional method can not satisfy the requirement.

In order to solve such a problem, a method in which an amine-substituted triazine compound and an aliphatic compound are mixed in a polyoxymethylene resin (Korean Published Unexamined Patent Publication No. 10-2010-0134636), a method of adding calcium carbonate and organic (WO00 / 2005/071011), a method of blending a conductive carbon and a polyurethane resin with a polyoxymethylene resin (JP-A-11-1603). However, the conventional polyoxymethylene resin compositions are often inadequate in view of the crystal properties suitable for use as actual structural parts of fuel pumps and door modules and the shrinkage rate after molding by such a method alone.

In order to compensate the crystallization characteristics, a method of producing a polyoxymethylene multi-component copolymer with at least one compound selected from trioxane, an oxyethylene compound and glycidyl phenyl ether, styrene oxide, and glycidyl naphthyl ether Open No. 3-126752). However, these methods are not economically suitable from the viewpoint of productivity and yield, so that mass production is often difficult.

Disclosure of the Invention The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a polyoxymethylene resin composition improved in rigidity, creep resistance and crystallinity compared to conventional polyoxymethylene resins.

Accordingly, the present invention provides, as a first preferred embodiment, a polyoxymethylene copolymer obtained by copolymerizing trioxane with an oxyethylene compound; 0.01 to 0.5 parts by weight of a polyoxymethylene terpolymer obtained by copolymerizing trioxane, an oxyethylene compound and a glycidyl compound with respect to 100 parts by weight of the polyoxymethylene copolymer.

The oxyethylene compound according to this embodiment may be one or more selected from the group consisting of ethylene oxide, 1,3-dioxolane, 1,3-dioxepane, and 1,3,5-trioxepane.

The polyoxymethylene terpolymer according to this embodiment may be obtained by copolymerizing 0.1 to 5 parts by weight of an oxyethylene compound and 0.001 to 1 part by weight of a glycidyl compound with respect to 100 parts by weight of trioxane.

The glycidyl compound according to this embodiment may be selected from the group consisting of glycidyl phenyl ether, styrene oxide, glycidyl naphthal ether, tetrahydrofuran, And may be at least one selected from the group consisting of Alkyl glycidyl ether and Glycidyl isopropyl ether.

The polyoxymethylene resin composition according to this embodiment has a tensile strength of 650 kgf / cm ² or more, a creep rupture time of 1200 min or more, a crystallization speed of 2.5 to 3.5 min, and a shrinkage ratio of 1/8 inch bar may be less than 2.60% on a specimen basis.

The polyoxymethylene terpolymer according to this embodiment may be obtained by copolymerizing 0.1 to 5 parts by weight of an oxyethylene compound and 0.001 to 1 part by weight of a glycidyl compound with respect to 100 parts by weight of trioxane.

The polyoxymethylene resin composition according to the present invention is excellent in high rigidity and high in-creep properties, has a small crystal size and a small shrinkage ratio after molding, and therefore can be used for automobiles (fuel pumps and door modules) And the like.

Hereinafter, the present invention will be described in detail.

The present invention relates to a polyoxymethylene copolymer obtained by copolymerizing trioxane with an oxyethylene compound; 0.01 to 0.5 parts by weight of a polyoxymethylene terpolymer obtained by copolymerizing trioxane, an oxyethylene compound and a glycidyl compound with respect to 100 parts by weight of the polyoxymethylene copolymer.

(A) copolymerizing 0.1 to 5 parts by weight of an oxyethylene compound with 100 parts by weight of trioxane to prepare a polyoxymethylene copolymer; (b) 0.01 to 0.2 parts by weight of a polyoxymethylene terpolymer obtained by copolymerizing trioxane, an oxyethylene compound and a glycidyl compound with respect to 100 parts by weight of the polyoxymethylene copolymer, and stabilizing the poly And a process for producing an oxymethylene resin composition.

Polyoxymethylene copolymer

In the present invention, the polyoxymethylene copolymer is a copolymer of trioxane and an oxyethylene compound, and may be a copolymer of 0.5 to 5.0 parts by weight of an oxyethylene compound per 100 parts by weight of trioxane.

The oxyethylene compound may be one or more selected from the group consisting of ethylene oxide, 1,3-dioxolane, 1,3-dioxepane, and 1,3,5-trioxepane, It can be a solan.

If the content of the oxyethylene compound is less than 0.5 parts by weight based on 100 parts by weight of the trioxane, there is a problem that the thermal stability of the polyoxymethylene copolymer is deteriorated. If the content is more than 5.0, the polymerization yield decreases, There is a problem that the post-shrinkage ratio becomes large.

The polymerized copolymer is then contacted immediately with the defoamer to stop the polymerization reaction. As the deactivation agent used herein, amine compounds such as triethylamine and tributylamine, hydroxides of alkali metals or alkaline earth metals, and other known deflocculants can be used.

The addition amount of the deflocculating agent is not particularly limited so as to stop the reaction due to the deactivation of the catalyst, but it is 1 to 10 mol based on 1 mol of the Lewis acid catalyst used.

The deflocculating agent is used in the form of a solution or a suspension. As the solvent to be used herein, an aliphatic or aromatic organic solvent such as hexane, cyclohexane, benzene, toluene, xylene, methylene chloride or the like can be used.

Polyoxymethylene terpolymer

In the present invention, the polyoxymethylene terpolymer is obtained by copolymerizing trioxane, oxyethylene compound and glycidyl compound, and the content thereof may be 0.01 to 0.2 parts by weight based on 100 parts by weight of the polyoxymethylene copolymer .

When the content of the polyoxymethylene terpolymer is less than 0.01 part by weight, there is a problem that the crystal properties are not complemented. When the content is more than 0.2 parts by weight, there is a problem that the improvement of the crystal properties is hardly effected and the mechanical properties are deteriorated.

The polyoxymethylene terpolymer may be obtained by copolymerizing 0.5 to 5 parts by weight of an oxyethylene compound and 0.001 to 1 part by weight of a glycidyl compound with respect to 100 parts by weight of trioxane.

The oxyethylene compound may be one or more selected from the group consisting of ethylene oxide, 1,3-dioxolane, 1,3-dioxepane, and 1,3,5-trioxepane. The content of the oxyethylene compound may be 100 parts by weight 0.5 to 5 parts by weight. If the content of the oxyethylene compound is less than 0.5 parts by weight, thermal stability is lowered and unzipping occurs. When the content of the oxyethylene compound is more than 5 parts by weight, the rigidity is greatly reduced.

(A) copolymerizing 0.5 to 5 parts by weight of an oxyethylene compound with 100 parts by weight of trioxane to prepare a polyoxymethylene copolymer; (b) 0.01 to 0.5 parts by weight of a polyoxymethylene terpolymer obtained by copolymerizing trioxane, an oxyethylene compound and a glycidyl compound with respect to 100 parts by weight of the polyoxymethylene copolymer, and stabilizing the poly And a process for producing an oxymethylene resin composition.

The step of preparing the polyoxymethylene copolymer in the step (a) may be carried out by adding an oxyethylene compound to trioxane and then performing cation random copolymerization using a Lewis acid catalyst to obtain polyoxymethylene having two or more bonding carbon atoms in the main chain Copolymers can be prepared.

The structure of the polyoxymethylene copolymer may have a branched structure and a crosslinked structure as well as a linear structure.

(- (OCH ₂ CH ₂ ) _n -), oxypropylene (- (OCH ₂ CH ₂ CH ₂ ) _n -) as a constituent unit of the comonomer other than the oxymethylene group which is the main chain of the polyoxymethylene copolymer, And branched oxyalkylene groups having 2 to 10 carbon atoms such as oxybutylene (- (OCH ₂ CH ₂ CH ₂ CH ₂ ) _n -). Among them, branched oxy groups having 2 to 4 carbon atoms An alkylene group, and particularly an oxyethylene group.

In the step (b), the polyoxymethylene copolymer is stabilized by adding a polyoxymethylene terpolymer to the polyoxymethylene copolymer produced in step (a). In the polyoxymethylene copolymer, unstable terminal groups are present in a highly unstable state This requires a stabilization step to remove unstable ends. In the stabilization step, the polyoxymethylene copolymer and the polyoxymethylene terpolymer are melt-kneaded at 180 to 260 ° C. using an uniaxial or twin-screw vented extruder to stabilize the pelletized polyoxymethylene resin composition Can be obtained. to be.

The polyoxymethylene resin composition of the present invention may contain a filler such as calcium carbonate, clay, silicon oxide, mica powder, a glass fiber, a carbon fiber, a polyamide (amide) fiber Antioxidants such as hindered phenol compounds and phosphate compounds, releasing agents such as ethylene bis stearate, polyethylene wax, hindered amine compounds, benzophenone ( Benzophenone compounds, benzotriazole compounds, formaldehyde additives such as melamine, guanidine, and Dicyan diamide, lubricants, and the like. . ≪ / RTI >

The polyoxymethylene resin composition thus prepared had a tensile strength of 650 kgf / cm ² or more, a creep rupture time of 1200 min or more, a crystallization speed of 2.5 to 3.5 min, and a shrinkage ratio of 1/8 inch bar It may be 2.60% or less on a specimen basis.

The polyoxymethylene resin composition having the above-described physical properties is excellent in high rigidity and high in-creep properties, and is suitable for use in automobiles and other industrial products requiring a crystal property suitable for use as a structural component and a shrinkage ratio after molding.

Hereinafter, the present invention will be described in detail based on preferred embodiments. The present invention is not limited to the following examples.

Examples 1 to 10

1,3-dioxolane (C ₃ H ₆ O ₂ , molecular weight: 74.08 g / mol) was added to trioxane ((CH ₂ O) ₃ , molecular weight: 90.08 g / mol) according to the composition shown in Table 1 Then, a Lewis acid catalyst (BF ₃ OEt ₂ , molecular weight: 103.84 g / mol) was added, and cation random copolymerization was carried out to prepare a polyoxymethylene copolymer. The polyoxymethylene copolymer was prepared by using a uniaxially extruded tubular reactor designed to be pulverized at the same time as the polymerization, with a polymerization time of about 2 minutes or more and a polymerization temperature of 80 to 85 ° C.

A polyoxymethylene terpolymer was added to the polyoxymethylene copolymer in the stabilization step to prepare a polyoxymethylene resin composition.

In the stabilization step, a polyoxymethylene copolymer and a polyoxymethylene terpolymer were mixed using a twin-screw extruder at a temperature of 240-245 DEG C for melt mixing.

Comparative Example 1

A polyoxymethylene resin composition was prepared in the same manner as in Example 1 except that the content of each component was changed according to the composition shown in Table 1.

Property evaluation

The properties of the polyoxymethylene resin compositions prepared in Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 2.

The tensile strength

: Measured according to ASTM D-638 standard.

Creep test

: A creep test machine was used to compare the ISO type tensile test specimen with a specimen with a load stress of 40 MPa and a temperature of 65 degrees until fracture of the tensile test specimen.

Crystallization speed

: After melting by DSC, the time until the crystal was formed by isothermalization at 153 degrees was measured.

Shrinkage rate

: The tensile test specimens of ASTM type were stored at room temperature for 24 hours, and the difference in size of the test specimens was compared.

 (Unit: parts by weight) division Polyoxymethylene copolymer Polyoxymethylene terpolymer
(Based on 100 parts by weight of the polyoxymethylene copolymer) Trioxane 1,3-dioxolane Example 1 100 1.5 0.05 Example 2 100 2.0 0.05 Example 3 100 2.5 0.05 Example 4 100 3.0 0.05 Example 5 100 4.0 0.05 Example 6 100 2.0 0.25 Example 7 100 2.0 0.075 Example 8 100 2.0 0.1 Example 9 100 2.0 0.2 Example 10 100 6.0 0.05 Comparative Example 1 100 2.0 0.005

division The tensile strength
(kgf / cm2) Creep
Breaking time (h) Crystallization speed
(min) Shrinkage rate
(%) Example 1 658 1220 3.11 2.57 Example 2 658 1225 3.75 2.56 Example 3 643 1150 3.68 2.60 Example 4 630 1100 4.42 2.62 Example 5 611 1085 6.58 2.65 Example 6 651 1220 5.97 2.56 Example 7 660 1235 3.22 2.52 Example 8 665 1250 2.93 2.50 Example 9 666 1250 2.55 2.49 Example 1 550 1000 10.58 2.75 Comparative Example 1 650 1200 6.67 2.67

As a result of evaluation of physical properties, as shown in Table 2, in the polyoxymethylene resin composition, the lower the 1,3-dioxolane content in the polyoxymethylene copolymer, the higher the content of the polyoxymethylene terpolymer, The crystallization rate is fast and the shrinkage rate after molding is low.

Claims (6)

A polyoxymethylene copolymer obtained by copolymerizing trioxane with an oxyethylene compound;
Based on 100 parts by weight of the polyoxymethylene copolymer,
0.01 to 0.5 part by weight of a polyoxymethylene terpolymer obtained by copolymerizing trioxane, an oxyethylene compound and a glycidyl compound. The method according to claim 1,
Wherein the oxyethylene compound is at least one selected from the group consisting of ethylene oxide, 1,3-dioxolane, 1,3-dioxepane, and 1,3,5-trioxepane. The method according to claim 1,
Wherein the polyoxymethylene copolymer is obtained by copolymerizing 0.5 to 5 parts by weight of an oxyethylene compound with respect to 100 parts by weight of trioxane. The method according to claim 1,
Wherein the polyoxymethylene terpolymer is obtained by copolymerizing 0.5 to 5 parts by weight of an oxyethylene compound and 0.001 to 1 part by weight of a glycidyl compound per 100 parts by weight of trioxane. The method according to claim 1,
The glycidyl compound may be selected from the group consisting of glycidyl phenyl ether, styrene oxide, glycidyl napthal ether, tetrahydrofuran, alkyl glycidyl ether (Alkyl glycidyl ether, and glycidyl isopropyl ether. The polyoxymethylene resin composition according to claim 1, wherein the polyoxyethylene resin is at least one selected from the group consisting of glycidyl ether and glycidyl isopropyl ether. The method according to claim 1,
Wherein the polyoxymethylene resin composition has a tensile strength of 650 kgf / cm ² or more, an creep rupture time of 1200 min or more, a crystallization speed of 2.5 to 3.5 min, and a shrinkage ratio after molding of 1/8 inch bar 2.60% or less of the polyoxymethylene resin composition.