# US 2013/0153121 A1 · Methods, apparatus and systems for reducing warpage in polymers with continuous fibers

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- Number: US 2013/0153121 A1
- Document ID: US20130153121A1
- Status: Published application
- Kind: A1
- Application number: 13/330,444
- Filed: 2011-12-19
- Published: 2013-06-20
- Earliest claimed: 2011-12-19
- Assignees: Toyota Motor Engineering & Manufacturing North America, Inc.
- Inventors: Umesh N. Gandhi
- Web page: https://patentgrep.com/patent/US20130153121A1

## CPC

- B29C 70/56: Tensioning reinforcements before or during shaping
- B32B 27/12: next to a fibrous or filamentary layer
- B32B 37/0015: {to avoid warp or curl}
- B32B 2262/101: Glass fibres
- B32B 2305/08: Reinforcements
- B32B 2305/10: Fibres of continuous length
- Y10T 428/24942: including components having same physical characteristic in differing degree
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Apparatus, systems and/or methods are provided to substantially reduce warping of a reinforced polymer. For example, by pre-stressing a glass component proportional to the difference between coefficients of linear expansions of glass and polymers, warping may be reduced when the resulting glass-polymer compound is cooled.

## Claims

### Claim at position 1

-10. (canceled)

### Claim 11

A method for reducing the warping of a molded polymer-continuous fiber compound, the method comprising:
pre-stressing a layer of continuous fiber;
molding the layer of continuous fiber to a layer of polymer including a heating process; and
cooling the layer of continuous fiber and the layer of polymer such that the resulting compound is substantially flat.

### Claim 12 (depends on 11)

The method of claim 11, wherein cooling the layer of continuous fiber includes releasing of the pre-stress.

### Claim 13 (depends on 12)

The method of claim 12, wherein cooling the layer of continuous fiber below a predetermined threshold temperature triggers release of the pre-stress.

### Claim 14 (depends on 13)

The method of claim 13, wherein the release of the pre-stress causes the layer of continuous fiber to shrink.

### Claim 15 (depends on 11)

The method of claim 11, further comprising determining the degree of pre-stressing based on a coefficient of a linear expansion of a material of the continuous fiber layer and a coefficient of a linear expansion of a material of the polymer.

### Claim 16 (depends on 11)

The method of claim 11, further comprising the addition of an inorganic filler, an additive, or a modifier to the layer of continuous fiber or the layer of polymer.

### Claim 17

A method of reducing the warping of a molded glass-reinforced polymer, the method comprising:
pre-stressing a continuous glass fiber tape by stretching and holding the continuous glass fiber tape horizontally and/or vertically by means of a device;
adding a heated polymer to the pre-stressed continuous glass fiber tape to form a fiber-reinforced-polymer (FRP) composite;
molding the FRP composite;
cooling the FRP composite; and
releasing the continuous glass fiber tape from the pre-stress applied causing the FRP composite to be substantially unwarped.

### Claim 18 (depends on 17)

The method of claim 17, wherein cooling of the FRP composite below a predetermined threshold temperature triggers the releasing of the continuous glass fiber tape from the pre-stress.

### Claim 19 (depends on 17)

The method of claim 17, further comprising determining the degree of pre-stressing based on a coefficient of a linear expansion of a material of the continuous glass fiber tape and a coefficient of a linear expansion of a material of the polymer.

### Claim 20 (depends on 17)

The method of claim 17, further comprising the addition of an inorganic filler, an additive, or a modifier to the continuous glass fiber tape or the polymer.