CN1342723A

CN1342723A - High-toughness acetal composition and its preparing process

Info

Publication number: CN1342723A
Application number: CN 00124702
Authority: CN
Inventors: 张师军; 乔金梁; 张薇; 邵静波; 尹华; 翟仁立; 张晓红; 段淑清; 刘轶群; 高建民; 李魁; 宋志海; 魏根栓; 黄帆
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp; China Petrochemical Corp
Priority date: 2000-09-13
Filing date: 2000-09-13
Publication date: 2002-04-03
Anticipated expiration: 2020-09-13
Also published as: CN1166736C

Abstract

A high-toughness paraform composition is prepared by mixing the rubber particles (grain size 20-200 nm) with paraform in weight ratio of (0.5-50):(50-99.5). Its advantages are balanced rigidity and toughness, and stable performance.

Description

A kind of high-toughness acetal composition and preparation method thereof

The present invention relates to a kind of high-toughness acetal composition and preparation method thereof, say further, the present invention relates to utilize rubber and polyoxymethylene blended and high-toughness acetal composition and this kind preparation of compositions method that make.

It is a kind of engineering plastics with general high-performance that the polyoxymethylene (POM) of the title of plastic-metal is arranged, and it is divided into is two types, as by the homopolymerization type polyoxymethylene of U.S. Dupont company exploitation and the copoly type polyoxymethylene of U.S. Celanese company exploitation.Advantages such as the polyoxymethylene rigidity is big, self-lubricating property good, antifatigue, abrasion are little, hardness is big.But toughness is relatively poor when it is used in some fields, therefore usually needs its impact is improved.In the prior art, typically using elastomerics carries out toughness reinforcing to polyoxymethylene.The German Hoechst company that selects as U.S. Pat 4517319 described U.S. Dupont companies that isocyanic acid polyurethanes copolymer elastomer reinforced polyformaldehyde, European patent EP 120711 and EP121407 put down in writing for use selects for use diolefine graftomer elastic body toughening polyoxymethylene and European patent EP 117664 companies of described Japanese Asahi Chemical Industry to select styrene block copolymer elastomer reinforced polyformaldehyde etc. for use.

Ooze theory according to the exceeding of plastic toughening that the Souheng Wu the eighties of du pont company proposes, point out that in rubber toughened plastics, dispersive rubber phase particle diameter is more little, the easy more generation brittle-ductile transition of toughened plastics.Pass through in the technology of elastic body toughening polyoxymethylene existing, with elastomerics as toughner and polyoxymethylene blended and obtain reinforced polyformaldehyde, have the following disadvantages: (1) is under the blending condition of present rubber and plastic processing, elastomerics particle diameter as disperse phase is difficult to be controlled at small range, and average elastomerics particle dia is greater than 200nm.If will realize brittle-ductile transition, then need the elastomerics of big umber, thereby cause the reinforced polyformaldehyde inflexible to reduce; (2) the particle diameter instability of elastomerics disperse phase, along with the variation of factors such as course of processing middle shear rate, the disperse phase particle diameter in the reinforced polyformaldehyde is always in variation; (3) elastomerics disperse phase particle diameter is very inhomogeneous; (4) elastomer content can not surpass 40%, otherwise is prone to " Hai-Hai " phase structure, even phase reversion occurs, makes the degradation of reinforced polyformaldehyde.

Therefore, it is little to the purpose of this invention is to provide a kind of contained rubber phase median size, and even, the stable high-toughness acetal composition of rubber size.Phase reversion also do not occur even its rubber content reaches 70%, rubber remains disperse phase.When having higher toughness, this high-toughness acetal composition also has rigidity preferably.

Another object of the present invention provides the preparation method of described high-toughness acetal composition, and this method technology is simple, easy handling.

High-toughness acetal composition of the present invention is achieved in that

High-toughness acetal composition of the present invention comprises following component blend and gets: polyoxymethylene and median size are the rubber particles of 20～200nm.Wherein the weight ratio of rubber particles and polyoxymethylene is 0.5: 99.5～50: 50, preferred 5: 95-30: 70.The median size of rubber particles is preferably between 50～150nm.This modified polyacetal has good strong and unyielding equilibrated over-all properties.

In this high-toughness acetal composition, can be selected from homopolymerization type polyoxymethylene or copoly type polyoxymethylene as the polyoxymethylene of external phase.

In this high-toughness acetal composition, be preferably the rubber particles of equal phase structure as the rubber particles of disperse phase, it is the cross-linked rubber particle of gel content 〉=60% preferably.This kind rubber particles can adopt according to the inventor in the prepared fully vulcanized powder rubber of the Chinese patent 99125530.5 of on December 3rd, 1999 application, comprises at least a of fully vulcanized powder rubbers such as form of finely divided powder, mehtod carboxylic styrene-butadiene rubber or form of finely divided powder, mehtod acrylic elastomer.This kind fully vulcanized powder rubber is meant that gel content reaches more than 60%, and need not with separant after the drying is free flowable rubber particle.This powdered rubber is with rubber particles particle diameter fixed by cross-linking radiation.

The preparation method of high-toughness acetal composition of the present invention is: with polyoxymethylene and median size is that the rubber particles of 20～200nm makes high-toughness acetal composition by blend.The median size of rubber particles is preferably between 100～150nm.This kind rubber particles is preferably the rubber particles of equal phase structure, and it is the cross-linked rubber particle of gel content 〉=60% preferably.The weight ratio of rubber particles and polyoxymethylene is 0.5: 99.5-50: 50, preferred 5: 95-30: 70.

When preparation high-toughness acetal composition of the present invention, polyoxymethylene can be selected from homopolymerization type polyoxymethylene or copoly type polyoxymethylene.

Rubber particles can adopt according to the inventor in the prepared fully vulcanized powder rubber of the Chinese patent 99125530.5 of on December 3rd, 1999 application in present method, and it can comprise at least a of fully vulcanized powder rubbers such as form of finely divided powder, mehtod carboxylic styrene-butadiene rubber or form of finely divided powder, mehtod acrylic elastomer.This kind fully vulcanized powder rubber is meant that gel content reaches more than 60%, and need not with separant after the drying is free flowable rubber particle.This powdered rubber is with rubber particles particle diameter fixed by cross-linking radiation.When fully vulcanized powder rubber mixed with polyoxymethylene, these particles were dispersed in the polyoxymethylene very easily uniformly and stably, were difficult for cohesion, can keep the particle diameter of the preceding powdered rubber of blend substantially.

Fully vulcanized powder rubber can add or add with undried crosslinked emulsions form with the crosslinked powder morphology of exsiccant.

In preparation process, the blending temperature of material is used blending temperature in the common polyoxymethylene processing, generally at 165～195 ℃.In addition, according to the processing needs, can in the blend material, add the conventional auxiliary agent and the expanding material of plastic working in right amount.

The employed blending equipment of present method is the general blending equipment in the rubber and plastic processing industry, can be mill, Banbury mixer, single screw extrusion machine or twin screw extruder etc.

High-toughness acetal composition of the present invention, contained rubber phase particle diameter is little, and particle diameter is even, stable, also is easy to reach high rubber and plastic ratio; It has high-rigidity high-toughness and good processing forming, is applicable to very extensive fields.

Simple, the easy handling of method technology for preparing high-toughness acetal composition of the present invention.

Further describe the present invention below in conjunction with embodiment, scope of the present invention is not subjected to the restriction of these embodiment.Scope of the present invention proposes in claims.

Embodiment 1-4:

(trade mark of producing in Yanshan Petrochemical is in the XSBRL-54B1 carboxyl styrene-butadiene emulsion with the form of finely divided powder, mehtod carboxylic styrene-butadiene rubber, after sneaking into the crosslinking coagent Isooctyl acrylate monomer by 3% of the dried glue weight of carboxyl styrene-butadiene emulsion, carry out radiation vulcanization, irradiation dose is 2.5Mrad, spray-dried obtaining, median size is 150nm, and gel content is 92.6%) and polyoxymethylene (Japanese Asahi Kasei Corporation produces the copoly type trade mark 4520) and calcium stearate (the long positive chemical plant production chemical pure in Beijing), polyethylene wax (Beijing University of Chemical Technology's production chemical pure), antioxidant 1010 (vapour Ba Jiaji production) and superfine talcum powder (the He Beilu county produces 1250 orders) uniform mixing.Adopt the ZSK-25 twin screw extruder blend granulation of German WP company, each section of forcing machine temperature is respectively: 175 ℃, 180 ℃, 185 ℃, 185 ℃, 180 ℃ and 175 ℃ (head temperature).Concrete prescription sees Table 1, and wherein the component concentration of form of finely divided powder, mehtod carboxylic styrene-butadiene rubber and polyoxymethylene is all in parts by weight, and other auxiliary agent is to account for the weight percentage of each component summation.The pellet oven dry is carried out every Mechanics Performance Testing after injection moulding is made the standard batten.Testing standard and results of property are as shown in table 1.

Comparative Examples 1:

After twin screw extruder blend granulation, all the other conditions are identical with embodiment 1 with the polyoxymethylene among the embodiment 1 and calcium stearate, antioxidant 1010, polyethylene wax and superfine talcum powder uniform mixing.Concrete prescription, testing standard and results of property are as shown in table 1.

Comparative Examples 2:

After twin screw extruder blend granulation, all the other conditions are identical with embodiment 1 with calcium stearate, antioxidant 1010, polyethylene wax and the superfine talcum powder uniform mixing described in the polyoxymethylene among the embodiment 1 and acrylic elastomer (du pont company Lucite44-N) and the embodiment 1.Prescription sees Table 1, and wherein the component concentration of acrylic elastomer and polyoxymethylene is all in parts by weight, and other auxiliary agent is to account for the weight percentage of each component summation.Testing standard and results of property are as shown in table 1.

Embodiment 5-8:

With form of finely divided powder, mehtod carboxylic styrene-butadiene rubber (with embodiment 1) and polyoxymethylene (the production homopolymerization type trade mark Delirin100 of U.S. Dupont company) and calcium stearate (the long positive chemical plant production chemical pure in Beijing), polyethylene wax (Beijing University of Chemical Technology's production chemical pure), antioxidant 1010 (vapour Ba Jiaji production) and superfine talcum powder (the He Beilu county produces 1250 orders) uniform mixing.Adopt the ZSK-25 twin screw extruder blend granulation of German WP company, each section of forcing machine temperature is respectively: 190 ℃, 195 ℃, 205 ℃, 210 ℃, 205 ℃ and 205 ℃ (head temperature).Concrete prescription sees Table 2, and wherein the component concentration of form of finely divided powder, mehtod carboxylic styrene-butadiene rubber and polyoxymethylene is all in parts by weight, and other auxiliary agent is to account for the weight percentage of each component summation.The pellet oven dry is carried out every Mechanics Performance Testing after injection moulding is made the standard batten.Testing standard and results of property are as shown in table 2.

Comparative Examples 3

After twin screw extruder blend granulation, all the other conditions are identical with embodiment 5 with the polyoxymethylene among the embodiment 5 and calcium stearate, antioxidant 1010, polyethylene wax and superfine talcum powder uniform mixing.Concrete prescription, testing standard and results of property are as shown in table 2.

Table 1

	Embodiment 1	Embodiment 2	Embodiment 3	Embodiment 4	Comparative Examples 1	Comparative Examples 2	Unit	Standard
	Embodiment 1	Embodiment 2	Embodiment 3	Embodiment 4	Comparative Examples 1	Comparative Examples 2	Unit	Standard	Polyoxymethylene	??90	??85	??79	??72	??100	??85	????——	——
The form of finely divided powder, mehtod carboxylic styrene-butadiene rubber	??10	??15	??21	??28	??——	??——	????——	——	Polyoxymethylene	??90	??85	??79	??72	??100	??85	????——	——
	??10	??15	??21	??28	??——	??——	????——	——	Acrylic elastomer	??——	??——	??——	??——	??——	??15	????——	——
Calcium stearate	??0.7％	??0.7％	??0.7％	??0.7％	??0.7％	??0.7％	????——	——	Acrylic elastomer	??——	??——	??——	??——	??——	??15	????——	——
Calcium stearate	??0.7％	??0.7％	??0.7％	??0.7％	??0.7％	??0.7％	????——	——	Polyethylene wax	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	????——	——
Superfine talcum powder	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	????——	——	Polyethylene wax	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	????——	——
Superfine talcum powder	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	??0.3％	????——	——	Antioxidant 1010	??0.4％	??0.4％	??0.4％	??0.4％	??0.4％	??0.4％	????——	——
Tensile strength	??56.5	??54.3	??48.3	??41.2	??60.2	??50.1	????MPa	ASTM?D638	Antioxidant 1010	??0.4％	??0.4％	??0.4％	??0.4％	??0.4％	??0.4％	????——	——
Tensile strength	??56.5	??54.3	??48.3	??41.2	??60.2	??50.1	????MPa	ASTM?D638	Elongation at break	??45	??62	??78	??215	??30	??42	????％	ASTM?D638
Flexural strength	??76.8	??67.3	??61.2	??46.7	??82.5	??64.5	????MPa	ASTM?D790	Elongation at break	??45	??62	??78	??215	??30	??42	????％	ASTM?D638
Flexural strength	??76.8	??67.3	??61.2	??46.7	??82.5	??64.5	????MPa	ASTM?D790	Modulus in flexure	??2.16	??1.81	??1.69	??1.35	??2.34	??1.83	????GPa	ASTM?D790
The socle girder notched Izod impact strength	??102	??189	??356	??562	??42	??146	????J/m	ASTM?D256	Modulus in flexure	??2.16	??1.81	??1.69	??1.35	??2.34	??1.83	????GPa	ASTM?D790
The socle girder notched Izod impact strength	??102	??189	??356	??562	??42	??146	????J/m	ASTM?D256	Heat-drawn wire (1.82MPa)	??92.7	??83.5	??72.3	??63.2	??110	??84.2	????℃	ASTM?D648

Table 2

	Embodiment 5	Embodiment 6	Embodiment 7	Embodiment 8	Comparative Examples 3	Unit	Standard
	Embodiment 5	Embodiment 6	Embodiment 7	Embodiment 8	Comparative Examples 3	Unit	Standard	Polyoxymethylene	????90	????85	????79	????72	????100	????——	?——
The form of finely divided powder, mehtod carboxylic styrene-butadiene rubber	????10	????15	????21	????28	????——	????——	?——	Polyoxymethylene	????90	????85	????79	????72	????100	????——	?——
	????10	????15	????21	????28	????——	????——	?——	Calcium stearate	????0.9％	????0.9％	????0.9％	????0.9％	????0.9％	????——	?——
Polyethylene wax	????0.4％	????0.4％	????0.4％	????0.4％	????0.4％	????——	?——	Calcium stearate	????0.9％	????0.9％	????0.9％	????0.9％	????0.9％	????——	?——
Polyethylene wax	????0.4％	????0.4％	????0.4％	????0.4％	????0.4％	????——	?——	Superfine talcum powder	????0.3％	????0.3％	????0.3％	????0.3％	????0.3％	????——	?——
Antioxidant 1010	????0.4％	????0.4％	????0.4％	????0.4％	????0.4％	????——	?——	Superfine talcum powder	????0.3％	????0.3％	????0.3％	????0.3％	????0.3％	????——	?——
Antioxidant 1010	????0.4％	????0.4％	????0.4％	????0.4％	????0.4％	????——	?——	Tensile strength	????60.5	????55.1	????50.8	????43.9	????67.8	????MPa	?ASTM?D638
Elongation at break	????87	????108	????155	????280	????65	????％	?ASTM?D638	Tensile strength	????60.5	????55.1	????50.8	????43.9	????67.8	????MPa	?ASTM?D638
Elongation at break	????87	????108	????155	????280	????65	????％	?ASTM?D638	Flexural strength	????85.6	????70.5	????51.1	????53.2	????95.6	????MPa	?ASTM?D790
Modulus in flexure	????2.37	????1.92	????1.61	????1.38	????2.68	????GPa	?ASTM?D790	Flexural strength	????85.6	????70.5	????51.1	????53.2	????95.6	????MPa	?ASTM?D790
Modulus in flexure	????2.37	????1.92	????1.61	????1.38	????2.68	????GPa	?ASTM?D790	The socle girder notched Izod impact strength	????182	????267	????425	????672	????123	????J/m	?ASTM?D256
Heat-drawn wire (1.82MPa)	????111.7	????92.5	????75.6	????67.9	????135.3	????℃	?ASTM?D648	The socle girder notched Izod impact strength	????182	????267	????425	????672	????123	????J/m	?ASTM?D256

Claims

1. high-toughness acetal composition, it is characterized in that this kind high-toughness acetal composition is to comprise following component blend and get: polyoxymethylene and median size are the rubber particles of 20～200nm, and the weight ratio of rubber particles and polyoxymethylene is 0.5: 99.5-50: 50.

2. high-toughness acetal composition according to claim 1 is characterized in that described polyoxymethylene comprises homopolymerization type polyoxymethylene or copoly type polyoxymethylene.

3. high-toughness acetal composition according to claim 1, the average particle size range that it is characterized in that described rubber particles is 50～150nm.

4. high-toughness acetal composition according to claim 1 is characterized in that described rubber particles is the rubber particles of equal phase structure.

5. high-toughness acetal composition according to claim 4 is characterized in that described rubber particles is the cross-linked rubber particle of gel content 〉=60%.

6. high-toughness acetal composition according to claim 5 is characterized in that described rubber is fully vulcanized powder rubber.

7. high-toughness acetal composition according to claim 6 is characterized in that described fully vulcanized powder rubber comprises at least a of following fully vulcanized powder rubber: form of finely divided powder, mehtod carboxylic styrene-butadiene rubber or form of finely divided powder, mehtod acrylic elastomer.

8. high-toughness acetal composition according to claim 1, the weight ratio that it is characterized in that described rubber particles and polyoxymethylene is 1: 99-30: 70.

9. method for preparing each described high-toughness acetal composition of claim 1-8, it is characterized in that with polyoxymethylene and median size being that the rubber particles blend of 20～200nm makes high-toughness acetal composition, the weight ratio of rubber particles and polyoxymethylene is 0.5: 99.5-50: 50.

10. preparation method according to claim 9 is characterized in that described rubber particles is a fully vulcanized powder rubber.

11., it is characterized in that described fully vulcanized powder rubber adds with crosslinked powder morphology of exsiccant or undried crosslinked emulsions form according to each described preparation method of claim 10.