EP0368312A2
Expired / Lapsed
EP
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Carbon fiber chopped strands and method of production thereof
Assignee: Teijin Ltd
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Filing: 1989-11-09
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Granted: —
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Expires: 2009-11-09
Abstract
Abstract A carbon fiber chopped strands suitable for use in production of a composite with a matrix material, which have a circular or elliptical cross-section, wherein carbon fiber filaments are bundled by a sizing agent in an amount of from 1 to 10% by weight based on the chopped strand, and which have denseness of from 0.4 to 0.9 according to the formula below: where D denotes the average diameter of the chopped strands, d denotes the average diameter of filaments constituting the chopped strand and N denotes the number of the filaments, and a method for production thereof by impregnating a carbon fiber strand with a sizing agent in an amount of from 1 to 10% by weight based on the total weight of the chopped strand to form a sized strand, and then cutting the sized strand, thereby giving the denseness of from 0.4 to 0.9 according to the formula (1).
Inventors
- 👤 Minoru C/O Toho Rayon Co. Ltd. Hirai
- 👤 Hideaki C/O Toho Rayon Co. Ltd. Fukuizumi
- 👤 Masakazu C/O Toho Rayon Co. Ltd. Ataka
- 👤 Katsumi C/O Toho Rayon Co. Ltd. Nakama
- 👤 Yoh-Ichi C/O Toho Rayon Co. Ltd. Maeda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 20:56
CPC Classifications
D; D01; D01F; D01F11/00; D01F11/10; D01F11/14; C; C08; C08K; C08K7/00; C08K7/02; C08K7/04; C08K9/00; C08K9/08
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
82 words
Carbon fiber chopped strands having a circular or elliptical cross-section, wherein carbon fiber filaments are bundled by a sizing agent in an amount of from 1 to 10% by weight based on the total weight of the chopped strand, and which have denseness of from 0.4 to 0.9 according to the formula below: where D denotes the average diameter of the chopped strands, d denotes the average diameter of filaments constituting the chopped strand and N denotes the number of the filaments.
Claim 2
Dependent Claim
82 words
Carbon fiber chopped strands having a circular or elliptical cross-section, wherein carbon fiber filaments are bundled by a sizing agent in an amount of from 1 to 10% by weight based on the total weight of the chopped strand, and which have denseness of from 0.4 to 0.9 according to the formula below: where D denotes the average diameter of the chopped strands, d denotes the average diameter of filaments constituting the chopped strand and N denotes the number of the filaments.
Claim 3
Dependent Claim
23 words
The carbon fiber chopped strands as in claim 1, wherein the average diameter of the filaments (d) is from 1 to 40 µm.
Claim 4
Dependent Claim
21 words
The carbon fiber chopped strands as in claim 1, wherein the number of the filaments (N) is from 1,000 to 100,000.
Claim 5
Dependent Claim
25 words
The carbon fiber chopped strands as in claim 1, wherein the average diameter of the carbon fiber chopped strands is from 30 to 20,000 µm.
Claim 6
Dependent Claim
30 words
The carbon fiber chopped strands as in claim 1, wherein the ratio of the longest diameter to the shortest diameter of the elliptical cross section is from 1 to 1.3.
Claim 7
Dependent Claim
22 words
The carbon fiber chopped strands as in claim 1, wherein the length of the chopped strands is from 1 to 10 mm.
Claim 8
Dependent Claim
29 words
The carbon fiber chopped strands as in claim 1, wherein the sizing agent is at least one resin selected from the group consisting of thermosetting resins and thermoplastic resins.
Claim 9
Dependent Claim
71 words
The carbon fiber chopped strands as in claim 1, wherein the sizing agent is at least one resin selected from the group consisting of epoxy resins, urethane-modified epoxy resins, polyester resins, phenol resins, polyamide resins, polyurethane resins, polycarbonate resins, polyetherimide resins, polyamideimide resins, polystylylpyridine resins, polyimide resin, bismaleimide resins, polysulfone resins, polyethersulfone resins, epoxy-modified urethane resins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins, modified forms of the above resins and mixtures thereof.
Claim 10
Independent Claim
111 words
A method for the production of carbon fiber chopped strands, comprising impregnating a carbon fiber strand with a sizing agent in an amount of from 1 to 10% by weight based on the total weight of the chopped strand, controlling the average diameter of the strands to obtain the desired size and shape of the cross-section of the strands to thereby obtain a denseness of from 0.4 to 0.9 defined by formula (1), and then cutting the sized strands; where D denotes the average diameter of the chopped strands, d denotes the average diameter of the filaments constituting the carbon fiber chopped strand and N denotes the number of the filaments.
Claim 11
Independent Claim
111 words
A method for the production of carbon fiber chopped strands, comprising impregnating a carbon fiber strand with a sizing agent in an amount of from 1 to 10% by weight based on the total weight of the chopped strand, controlling the average diameter of the strands to obtain the desired size and shape of the cross-section of the strands to thereby obtain a denseness of from 0.4 to 0.9 defined by formula (1), and then cutting the sized strands; where D denotes the average diameter of the chopped strands, d denotes the average diameter of the filaments constituting the carbon fiber chopped strand and N denotes the number of the filaments.
Claim 12
Dependent Claim
40 words
The method for production of carbon fiber chopped strands as in claim 9, wherein the carbon fiber strand is impregnated with a solution or an emulsion of a sizing agent and then the carbon fiber strand is subjected to drying.
Claim 13
Dependent Claim
32 words
The method for production of carbon fiber chopped strands as in claim 10, wherein the concentration of the solution or an emulsion of the sizing agent is from 0.5 to 30 wt%.
Claim 14
Dependent Claim
50 words
The method for production of carbon fiber chopped strands as in claim 10, wherein 2 to 30 of twists are provided to the carbon fiber strand prior to the loss of tackiness or the completion of solidification of the sizing agent which has been applied to the carbon fiber strand.
Claim 15
Dependent Claim
32 words
The method for production of carbon fiber chopped strands as in claim 10, wherein the carbon fiber strand having 2 to 30 twists is impregnated with a solution of the sizing agent.
Claim 16
Dependent Claim
26 words
The method for production of carbon fiber chopped strands as in claim 10, wherein the impregnation is conducted at a temperature of from 10 to 50°C.
Claim 17
Dependent Claim
41 words
The method for production of carbon fiber chopped strands as in claim 9, wherein the carbon fiber strand is impregnated with a sizing agent while the sizing agent is in a molten state and then cooled to solidify the sizing agent.
Claim 18
Dependent Claim
51 words
The method for production of carbon fiber chopped strands as in claim 9, wherein the carbon fiber strand is impregnated with solid sizing agent particles, the impregnated carbon fiber strand is heated to melt the sizing agent, and then the impregnated carbon fiber strand is cooled to solidify the sizing agent.
Claim 19
Dependent Claim
32 words
Use of the carbon fiber chopped strands of claim 1, wherein the chopped strands are mixed with a thermoplastic resin, and the mixture is subjected to production of a composite by molding.
References Cited (Backward Citations)
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