JPH03217449A - Polyoxymethylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject polyoxymethylene resin composition excellent in mechanical strength, prevention of contact staining and odorless properties and suitable for units of mechanical systems in the field of electricity, electronics, automobile, etc., by blending a specified amount of 1,2,3-benzotriazole compound. CONSTITUTION:With (A) 100 pts.wt. polyoxymethylene resin, (B) one or more 1,2,3-benzotriazole compounds selected from 1,2,3-benzotriazole, 1,2,3-tolyltriazole, potassium salts thereof and sodium salts thereof are blended in an amount of 0.01-5 pts.wt., preferably 0.1-2 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyoxymethylene resin composition that has excellent mechanical properties, contact contamination prevention properties, and odorlessness.

[Prior Art] Polyoxymethylene resin is known as an engineering plastic with a good balance of mechanical strength and impact resistance, and is used in a wide range of fields as parts for electronic devices and automobile parts.

However, when polyoxymethylene resin is used for block members and internal parts of electrical and electronic equipment, there are problems such as metal contact parts such as copper becoming discolored due to corrosion or adhesion of organic compounds, resulting in contact failure. . When we investigated the cause of this problem, we found that formaldehyde is generated due to the decomposition of polyoxymethylene resin, which adheres to the contacts or corrodes the metal. As a method for suppressing the generation of formaldehyde, a method is known in which a formaldehyde scavenger such as melamine or polyamide is added to polyoxymethylene resin (Japanese Patent Publication No. 4422/1982). However, even if these methods are used, although the generation of formaldehyde can be suppressed to a certain extent, contact failure will gradually progress and new problems such as melamine resin adhesion will occur, so it is difficult to solve the problem of preventing contact contamination. was insufficient. Also,
A polyoxymethylene resin composition to which a special penzotriazole derivative is added is known as a composition with improved weather resistance (Japanese Patent Application Laid-Open No. 2001-195155), but the effect of preventing contact contamination is insufficient, and contact contamination may occur. There has been a strong desire to develop a resin composition with excellent prevention ability.

[i! Means for Solving the Problem] As a result of intensive studies by the present inventors to solve the above problem,
By adding a 1,2,3-benzotriazole compound to polyoxymethylene resin, contact failure of metal contact parts will not occur at all, without impairing the excellent mechanical properties of polyoxymethylene resin. Furthermore, we discovered the fact that there is no formaldehyde odor at all, which could not be expected from conventional knowledge, and led to the present invention.

That is, the present invention provides: (1) polyoxymethylene resin 10
1, 2 for 0 parts by weight. A resin composition containing 0.01 to 5 parts by weight of at least one of 3 to 3 penzotriazole compounds.

(2) Above 1. 2. 3-benzotriazole metal compound is 1, 2, 3 penzotriazole, 1. 2. The resin composition according to claim 1, which is one or more compounds selected from 2,3-tolyltriazole, or potassium salts and sodium salts of these compounds.

1, 2 used in the present invention. The 3-benzotriazole compound means a compound represented by general formula (A). (In the formula, R+ represents a hydrogen atom, an alkyl group having a degree prime number of 1 to 30, or a substituted alkyl group, and one or more of them may be bonded to any position on the benzene ring, and each may be the same or different. (X represents a hydrogen atom or a potassium or sodium atom.) Particularly preferable compounds include 1, 2. 3-
Benzol-liazole, 1, 2. 3-tolyltriazole, or the potassium derivatives of these compounds,
Examples include sodium salts.

The amount added is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, per 100 parts by weight of the polyoxymethylene resin.
Particularly preferably O. It is 1 to 2 parts by weight. 0.01
If it is less than 5 parts by weight, there is no effect of addition, and if it is more than 5 parts by weight, a bleed phenomenon may occur or the mechanical properties of the molded product may deteriorate, which is not preferable.

The polyoxymethylene resin used in the present invention is composed of an oxymethylene homopolymer and mainly oxymethylene units, and has at least one type of carbon atom having 2 to 2 carbon atoms in the polymer main chain.
means an oxymethylene copolymer containing 8 oxyalkylene units.

For example, oxymethylene homopolymers can be polymerized by introducing anhydrous formaldehyde into an organic solvent containing a basic polymerization catalyst such as an organic amine, an organic or inorganic tin compound, or a metal hydroxide. After the polymer is filtered, it is heated in acetic anhydride in the presence of sodium acetate to acetylate the terminal ends. The polyoxymethylene copolymer can be prepared by dissolving a cyclic oligomer of formaldehyde such as substantially anhydrous trioxane or tetraoxane and at least one cyclic ether as a copolymerization component in an organic solvent such as cyclohexane or benzene. Alternatively, after suspending, a Lewis acid catalyst such as boron trifluoride/diethyl etherate is added to polymerize, and unstable terminals are decomposed and removed. Alternatively, a premix of hetrioxane and copolymerization component/catalyst is introduced into a self-cleaning stirrer to carry out bulk polymerization without using any solvent. If desired, the catalyst is removed from this polymer by washing, and unstable terminals are further decomposed and removed to produce the polymer.

Particularly preferably, trioxane and a cyclic ether are subjected to bulk polymerization in the presence of a Lewis acid catalyst such as boron trifluoride/diethyl etherate, and then the general formula (B) is obtained.
This is a polymer obtained by adding a hindered amine compound represented by the formula to stop the polymerization reaction.

(In the formula, R2 represents a hydrogen atom or a monovalent organic residue having 1 to 3 carbon atoms. R3 to R8 represent an alkyl group having 1 to 5 carbon atoms, and each may be the same or different. (n represents an integer of 1 or more, and R7 represents an n-valent organic residue.) Preferred compounds as the cyclic ether as a copolymerization component include ethylene oxide, brobylene oxide, 1
．． 3-dioxolane, II 3-dioxane, 1,
3-dioxebane, 1. 3. Examples include El-trioxocane, shrimp chlorohydrin, phenylglycidyl ether, but especially ethylene oxide,
1,3-dioxolane and 1,3-dioxebane are preferred. The amount of copolymerization is 0.1 per oxymethylene unit.
~10 mol%, particularly preferably 0. It needs to be in the range of 2 to 6 mol%, and 0. If it is less than 1 mol%, the resulting composition will have low thermal stability, and if it is more than 10 mol%, its mechanical strength and moldability will be poor, which is not preferable.

Similarly, the amount of polymerization catalyst added is 0.001 to 0.00 parts by weight per 100 parts by weight of trioxane. The range is preferably 1 part by weight, particularly preferably 0.005 to 0.05 part by weight.

Moreover, the bulk polymerization reaction temperature is preferably in the range of θO to 120°C, particularly preferably in the range of 60 to 90'C.

Among the hindered amines that stop the polymerization reaction, bis(1, 2, 2, 6.
6-pentamethyl-4-biperidinyl) sebacate, bis(2, 2, 8. 8-tetramethyl-4-
piperidinyl) sebacate, 1. 2. 3.
Tetrakis 4-butanetetracarboxylic acid (2, 2
．． 8,θ-tetramethyl-4-biperidinyl) ester, poly[[6-(1, 1, 3. 3-tetramethylbutyl)amino1. 3. 5-triazine-2. 41 diyl] [2, 2.
e, 8-tetramethyl-4biperidinyl)imino]
Hexamethylene [(2,2,θ,θ-tetramethyl-4
-piperidinyl) iminococo.

The amount of the hindered amine compound added is preferably such that the number of moles of the hindered amine structure is equal to or more than the mole amount of the polymerization catalyst used. Even if the number of moles of the hindered amine structure is less than the number of moles of the polymerization catalyst used, a catalyst deactivation effect can be seen, but the heat resistance stability of the obtained polymer will decrease slightly, so the desired degree of heat resistance stability may be It is necessary to adjust the amount added accordingly. When the above hindered amine compound is used for polymerization reaction,
Since the catalyst is completely deactivated, it is possible to proceed to the next step without washing and removing the catalyst, which is very advantageous in terms of process.

As a method for producing the polyoxymethylene resin composition of the present invention, generally known methods can be employed. For example, in the polymerization or stabilization process of polyoxymethylene resin, 1. 2
．． A method of adding a 3-benzotriazole compound,
Polyoxymethylene resin and 1,2,3-benzotriazole compound may be mixed in the form of pellets, powder, or granules and melt processed as is, but it is also possible to melt-mix using a Banbury mixer, roll, extruder, etc. Can be adopted. Particularly preferred is a method of melt-mixing at a temperature of 150 to 250° C. using a single-screw or twin-screw extruder.

In addition, the composition of the present invention may contain fillers such as calcium carbonate, barium sulfate, clay, titanium oxide, silicon oxide, mica powder, glass beads, carbon fiber, glass fiber, and ceramic to the extent that the effects of the present invention are not impaired. Fibers, reinforcing agents such as aramid fibers and potassium titanate fibers, coloring agents (pigments, dyes), nucleating agents, fixing agents, mold release agents such as ethylene bisstearamide and polyethylene wax, and conductive agents such as carbon black. antioxidants such as hindered phenolic compounds, thioether compounds, and phosphite compounds; light stabilizers such as hindered amine compounds, penzophenone compounds, and penzotriazole compounds; and melamine, guanidine, nylon, and dicyandiamide. Additives such as formaldehyde scavengers, adhesives, lubricants, hydrolysis resistance improvers, and adhesion aids can be optionally included. The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

[Example] The present invention will be explained below with reference to Examples. Note that all percentages and parts in the examples are based on weight.

In addition, the mechanical properties, MI values, contact contamination prevention properties, and odorlessness of the molded articles shown in Examples and Comparative Examples were determined as follows.

・Molding: Using an injection molding machine with a 5 oz injection capacity, set the cylinder temperature to 190°C, the mold temperature to 65°C, and the molding cycle to 50 seconds to inject the ASTMI dumbbell test piece and the 7 Izod impact test piece. Molded.

- Mechanical properties: Using the ASTMI dumbbell test piece obtained by the above injection molding, tensile strength was measured according to the ASTM D-El38 method, and using an Izod impact test piece, A
Impact strength was measured according to the STM D-25El method.

・MI value = Using pellets dried for 3 hours in a hot air oven at 80°C, according to ASTM D-1238,
Measured at a temperature of 190°C and a load of 2190 grams.・Contact contamination prevention property: Put 10 grams of polyoxymethylene resin pellets in a 24 mm diameter test tube, and place 101 on top of it.
Place a 1x811x0.5111 copper plate and seal the test tube with a burner. Heat this in a hot air oven at 85℃ for 10
After heating for 00 hours, the seal was opened and the steel plate was taken out. Contact contamination was investigated by measuring the contact resistance value on the surface of the copper plate.

- Odorless property 2 In the above test, it was observed whether there was any odor, especially formaldehyde odor, when the seal was opened.

In the Examples and Comparative Examples, a polyoxymethylene resin (POM-1) manufactured by the method described below or a commercially available polyoxymethylene homobolymer (DuPont Delrin N50) was used.
0Nc10) (POM-2), commercially available polyoxymethylene cobolima (Duracon M90 manufactured by Polyplastics)
-44) (POM-3) was used.

・Manufacture of polyoxymethylene resin POM-1 Trioxane (22.5
kg/h), 1,3-dioxolane (700g/h
), and also supplied toopppm of boron trifluoride diethyl monoterate (2.5% benzene solution) and 500 ppm of methylal to trioxane, respectively.
Continuous polymerization was performed. Polymerization is carried out at an external jacket temperature of 80
The temperature was controlled at 100 rpm.

Methyral as a molecular weight regulator was dissolved in trioxane. In addition, 1,3-dioxolane and catalyst solution are
A premix zone was provided for premixing immediately before feeding to the 21 goo. The polymer is 22.3% as a white fine powder.
kg/h.

For 5 kg of fine powder obtained in this way, 13.5
g's "Sanol" LS785 C manufactured by Ciba Geigy,
A solution of bis(1. 2. 2. 6. 8-pentamethyl-4-biperidinyl) sebacate] dissolved in 20 ml of benzene was added, and the mixture was stirred for 10 minutes in a Henschel mixer to deactivate the catalyst. 'Irganox' 245 (manufactured by Ciba Geigy, (triethylene glycol bis[3-(3-1-butyl-5-methyl-4-hydroxyphenyl)probione}) 125g
．． 5 g of calcium stearate and 5 g of melamine were added and melted by heating at 210° C. for 10 minutes to obtain POM-1.

- Example 1 Polyoxymethylene resin POM-1 1 to too parts by weight, 2. 3-benzotriazole 0.2
Dry blend the weight parts, 45nφ, L/D=31
．． Melt and knead at 220°C in a vented twin-screw extruder No. 5,
Pellets were obtained by extrusion cutting into water. This MI
The value, mechanical properties, contact contamination prevention, and odor were investigated.

- Example 2 Of the descriptions in Example 1, l, 2. 1. instead of 3-benzotriazole. 2. 3-Tolyltriazole was used.・Example 3 Among the descriptions in Example 1, 1, 2. 1. instead of 3-benzotriazole. 2. The sodium salt of 3-benzotriazole was used.

・Example 4 Among the descriptions in Example 1, 1, 2. 1. instead of 3-benzotriazole. 2. The potassium salt of 3-tolyltriazole was used.

・Example 5 Of the descriptions in Example 1, 1, 2. The amount of 3-benzotriazole added was 0.01 part by weight.

・Example 6 Among the descriptions in Example 1, 1, 2. The amount of 3-benzotriazole added was 5.0 parts by weight.

・Example 7 Among those described in Example 2, polyoxymethylene resin POM-
POM-2 was used instead of 1.

・Example 8 Among those described in Example 1, polyoxymethylene resin POM-
POM-3 was used instead of 1. Also, 1, 2.
The amount of 3-benzotriazole added was adjusted to O. The amount was 1 part by weight.

・Example 9 Among those described in Example 2, polyoxymethylene resin POM-
POM-3 was used instead of 1. Comparative Example 1 The MI value, mechanical properties, contact contamination prevention properties, and odor of additive-free POM-1 were investigated.

- Comparative Example 2 Among the descriptions in Example 2, 1, 2. The amount of 3-tolyltriazole added was 0.005 parts by weight. - Comparative Example 3 Among the descriptions in Example 2, 1. 2. 3-} Adjust the amount of lyltriazole added to 7. The amount was 0 parts by weight.

・Comparative Example 4 Among those described in Comparative Example 1, polyoxymethylene resin POM-
POM-2 was used instead of 1.

- Comparative Example 5 Among the descriptions of Example 9, 1. 2. Melamine was used instead of 3-tolyltriazole.

- Comparative Example 6 Among the descriptions of Example 9, 1, 2. Nylon 8/8B/810 was used instead of 3-tolyltriazole.

Polyoxymethylene resin used in the table and 1,2,3-
The types and blending ratios of benzotriazole compounds and the obtained physical properties are shown. From the results shown in the table, it can be seen that the composition of the present invention has excellent contact contamination prevention properties and odorless properties without impairing the excellent mechanical properties peculiar to polyoxymethylene resins.

Margins below [Effects of the Invention] The present invention provides a polyoxymethylene resin composition that has excellent mechanical strength, contact contamination prevention properties, and odorlessness by blending a 1.2.3-benzotriazole compound with a polyoxymethylene resin. Since it can be used as a material, it is widely used as mechanical parts in the electrical/electronic and automobile fields.

Claims (2)

[Claims] (1) 1 per 100 parts by weight of polyoxymethylene resin
A resin composition containing 0.01 to 5 parts by weight of at least one of , 2,3-benzotriazole compounds. (2) The 1,2,3-benzotriazole compound is 1
, 2,3-benzotriazole, 1,2,3-tolyltriazole, or one or more compounds selected from potassium salts and sodium salts of these compounds.
The resin composition described.