Random mat and fiber-reinforced composite material

Patent metadata

Field	Value
Publication number	US-8946342-B2
Application number	US-201313956417-A
Country	US
Kind code	B2
Filing date	Aug 1, 2013
Priority date	Feb 1, 2011
Publication date	Feb 3, 2015
Grant date	Feb 3, 2015

Abstract

There is provided a random mat of the present invention including: reinforcing fibers having an average fiber length of 5 to 100 mm; and a thermoplastic resin,
wherein a fiber areal weight of the reinforcing fibers is from 25 to 3,000 g/m 2 , for a reinforcing fiber bundle (A) including the reinforcing fibers equivalent to or more than a critical single fiber number defined by formula (1), a ratio of the reinforcing fiber bundle (A) to a total amount of the reinforcing fibers in the mat is from 30 vol % to less than 90 vol %, and an average number (N) of the reinforcing fibers in the reinforcing fiber bundle (A) satisfies formula (2):

Critical single fiber number=600/ D   (1)

0.7×10 4 /D 2 <N <1×10 5 /D 2   (2)
wherein D is an average fiber diameter (μm) of single reinforcing fibers.

First claim

What is claimed is:

1. A random mat comprising: carbon fibers having an average fiber length of 5 to 100 mm; and a thermoplastic resin,
wherein a fiber areal weight of the carbon fibers is from 25 to 3,000 g/m 2 ,
the random mat comprises a carbon fiber bundle (A) in a ratio of from 30 vol % to less than 90 vol % to a total amount of the carbon fibers, the carbon fiber bundle (A) including the carbon fibers of a critical single fiber number defined by formula (1) or more, and
an average number (N) of single carbon fibers in the carbon fiber bundle (A) satisfies formula (2):
Critical single fiber number=600/D  (1)

0.7×10 4 /D 2 <N<1×10 5 /D 2   (2)

wherein D is an average single fiber diameter (μm) of the carbon fiber bundle (A).

2. The random mat according to claim 1 ,
wherein an existing amount of the thermoplastic resin in the random mat is from 50 to 1,000 parts by weight based on 100 parts by weight of the carbon fibers.

3. The random mat according to claim 1 ,
wherein the thermoplastic resin is present in fibrous or particulate form.

4. A method for producing a random mat according to claim 1 , comprising:
cutting a carbon fiber bundle;
introducing the cut carbon fiber bundle into a tube, and opening the carbon fiber bundle by blowing air thereto in the tube;
spreading and concurrently suctioning the opened carbon fibers, together with a fibrous or particulate thermoplastic resin, and spraying the carbon fibers and the thermoplastic resin onto a fixing part and;
fixing the cut carbon fibers and the thermoplastic resin which are sprayed to form a random mat comprising carbon fibers having an average fiber length of 5 to 100 mm; and a thermoplastic resin,
wherein a fiber areal weight of the carbon fibers is from 25 to 3,000 g/m 2 ,
the random mat comprises a carbon fiber bundle (A) in a ratio of from 30 vol % to less than 90 vol % to a total amount of the carbon fibers, the carbon fiber bundle (A) including the carbon fibers of a critical single fiber number defined by formula (1) or more, and
an average number (N) of single carbon fibers in the carbon fiber bundle (A) satisfies formula (2):
Critical single fiber number=600/D  (1)

0.7×10 4 /D 2 <N< 1×10 5 /D 2   (2)

wherein D is an average single fiber diameter (μm) of the carbon fiber bundle (A).

5. A carbon fiber reinforced composite material obtained by molding the random mat according to claim 1 .

Assignees

• Teijin Ltd

Inventors

• Konagai Yuhei
• Sonoda Naoaki
• Okimoto Noboru
• Hagihara Katsuyuki

Classifications

• C08K3/04 Primary

  Carbon · CPC title

• B29C70/12

  using fibres of short length, e.g. in the form of a mat {(non-woven fabrics per se D04H1/00)} · CPC title

• C08J5/042

  with carbon fibres · CPC title

• D04H1/732

  by fluid current, e.g. air-lay · CPC title

• B29C43/222

  characterised by the shape of the surface · CPC title