EP0229477A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Molecularly oriented, silane-crosslinked ultra-high-molecular-weight polyethylene molded article and process for preparation thereof
Assignee: Mitsui Chemicals Inc
•
Filing: 1986-11-28
•
Granted: —
•
Expires: 2006-11-28
Abstract
Abstract If ultra-high-molecular-weight polyethylene having an intrinsic viscosity (q) of at least 5 dug is grafted with a silane compound in the presence of a radical initiator and extrusion-molded and the extrudate is impregnated with a silanol condensation catalyst after or during drawing and is then exposed to water to effect crosslinking, there is obtained a novel molecularly oriented molded article in which increase of the melting temperature, which is not observed in conventional draw-molded or crosslinked molded articles of polyethylene, can be attained, and even if this molecularly oriented molded article is exposed to a temperature of 180°C for 10 minutes, the molded article is not fused but the shape is retained and even after this heat history, a high strength retention ratio can be maintained. In this draw-molded article, the adhesiveness and creep resistance are prominently improved while high elastic modulus and high tensile strength inherent to a draw-molded article of ultra-high-molecular-weight polyethylene are retained.
Inventors
- 👤 Kasuo Yagi
- 👤 Hitoshi Mantoku
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 17:11
CPC Classifications
C; C08; C08F; C08F255/00; C08F255/02; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/06; C08L43/00; C08L43/04; D; D01; D01F; D01F11/00; D01F11/04; D01F11/06; D01F6/00; D01F6/02; D01F6/04; C08L2207/00; C08L2207/06; C08L2207/068; C08L2312/00; C08L2312/08; C08L51/00; C08L51/06; C08L91/00
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
117 words
A molecularly oriented, silane-crosslinked ultra-high-molecular-weight polyethylene molded article, wherein when the molded article is analyzed in the constrained state by a differential scanning calorimeter, at least two crystal-melting peaks (Tp) appear at temperatures higher by at least 10'C than the inherent crystal-melting temperature (Tm) of the ultra-high-molecular-weight polyethylene obtained as the main melting peak at the second temperature elevation and the melting calorific value of the crystal-melting peaks (Tp) is at least 50% of the total melting calorific value, and the sum of calorific values of high temperature side melting peaks (Tpl) appearing at temperatures in the range of from (Tm + 35°C) to (Tm + 120°C) is at least 5% of the total melting calorific value.
Claim 2
Dependent Claim
117 words
A molecularly oriented, silane-crosslinked ultra-high-molecular-weight polyethylene molded article, wherein when the molded article is analyzed in the constrained state by a differential scanning calorimeter, at least two crystal-melting peaks (Tp) appear at temperatures higher by at least 10'C than the inherent crystal-melting temperature (Tm) of the ultra-high-molecular-weight polyethylene obtained as the main melting peak at the second temperature elevation and the melting calorific value of the crystal-melting peaks (Tp) is at least 50% of the total melting calorific value, and the sum of calorific values of high temperature side melting peaks (Tpl) appearing at temperatures in the range of from (Tm + 35°C) to (Tm + 120°C) is at least 5% of the total melting calorific value.
Claim 3
Dependent Claim
52 words
A molded article as claimed in claim 1, wherein the heat-resistant creep characteristic of the molded article is such that if the molded article is placed at 70'C under a load corresponding to 30% of the breaking load at room temperature, the molded article is not broken for at least 1 minute.
Claim 4
Dependent Claim
34 words
A molded article as claimed in claim 1 or 2, wherein after the molded article is heated at 180°C for 10 minutes, the molded article has a strength retention ratio of at least 60%.
Claim 5
Dependent Claim
40 words
A molded article as claimed in any one of claims 1 to 3, wherein the molded article contains a grafted silane in an amount of 0.01 to 5% by weight as the content of Si based on the ultra-high-molecular-weight polyethylene.
Claim 6
Dependent Claim
20 words
A molded article as claimed in any one of the preceding claims, which is in the form of a filament.
Claim 7
Dependent Claim
17 words
A molded article as claimed in claim 5, wherein the orientation degree (F) is at least 0.90.
Claim 8
Dependent Claim
28 words
A molded article as claimed in claim 5 or 6, wherein the elasticity modulus is at least 20 GPa and the tensile strength is at least 1.2 GPa.
Claim 9
Dependent Claim
74 words
A process for the preparation of a molecularly oriented, silane-crosslinked ultra-high-molecular-weight polyethylene molded article, which comprises heat-molding a composition comprising ultra-high-molecular-weight polyethylene having an intrinsic viscosity (n) of at least 5 dl/g, a silane compound, a radical initiator and a diluent, drawing the silane compound-grafted ultra-high-molecular-weight polyethylene molded article, impregnating the drawn molded article with a silanol condensation catalyst during or after drawing, and contacting the drawn molded article with water to effect crosslinking.
Claim 10
Dependent Claim
74 words
A process for the preparation of a molecularly oriented, silane-crosslinked ultra-high-molecular-weight polyethylene molded article, which comprises heat-molding a composition comprising ultra-high-molecular-weight polyethylene having an intrinsic viscosity (n) of at least 5 dl/g, a silane compound, a radical initiator and a diluent, drawing the silane compound-grafted ultra-high-molecular-weight polyethylene molded article, impregnating the drawn molded article with a silanol condensation catalyst during or after drawing, and contacting the drawn molded article with water to effect crosslinking.
Claim 11
Dependent Claim
47 words
A process according to claim 8, wherein the silane compound is a compound represented by the following formula: wherein R stands for an organic group containing a radical polymerizable ethylenic unsaturation, Y stands for a hydrolyzable organic group and n is a number of 1 or 2.
Claim 12
Dependent Claim
17 words
A process according to claim 8 or 9, wherein the silane compound is vinyltriethoxysilane, vinyltrimethoxysilane or vinyltris(methoxyethoxy)silane.
Claim 13
Dependent Claim
26 words
A process according to claim 8, 9 or 10, wherein the radical initiator is a radical initiator having a half-value period temperature of 100 to 200°C.
Claim 14
Dependent Claim
44 words
A process according to any one of claims 8 to 11, wherein the diluent is a solvent having a boiling point higher than the melting point of the ultra-high-molecular-weight polyethylene or a wax or a waxy substance having a compatibility with the ultra-high-molecular-weight polyethylene.
Claim 15
Dependent Claim
55 words
A process according to any one of claims 8 to 12, wherein the silane compound, the radical initiator and the diluent are incorporated in amounts of 0.1 to 10 parts by weight, 0.01 to 3.0 parts by weight and 9900 to 33 parts by weight, respectively, per 100 parts by weight of the ultra-high-molecular-weight polyethylene.
Claim 16
Dependent Claim
32 words
A process according to any one of claims 8 to 13, wherein the composition comprising the ultra-high-molecular-weight polyethylene, the silane compound, the radical initiator and the diluent is melt-extruded through a spinneret.
Claim 17
Dependent Claim
39 words
A process according to any one of claims 8 to 14, wherein the silane-grafted polyethylene molded article is drawn at a draw ratio of 5 to 80 in a heat medium at 40 to 16 0 ° C .
Claim 18
Dependent Claim
35 words
A process according to claim 15, wherein the heat medium is a solvent capable of removing the diluent by extraction and having a boiling point higher than the melting point of the molded article composition.
Claim 19
Dependent Claim
27 words
A process according to any one of claims 8 to 16, wherein the silanol condensation catalyst is a dialkyl tin dicarboxylate, an organic titanate or lead naphthenate.
Claim 20
Dependent Claim
32 words
A process according to any one of claims 8 to 17, wherein crosslinking is effected by contacting the drawn molded article with water at 50 to 130°C for 3 to 24 hours.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.