JP2969178B2 - Method for producing preformed continuous strand mat - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a mat capable of preforming continuous strands. In one of its more specific aspects, the present invention relates to a method for matting from a continuous strand mat that is heated and formed into a desired shape by bending or pulling using a mold or screen. A method of producing mat preforms follows. The mat is then cooled and fixed in shape, and the pre-formed mat can be handled in the next forming operation.

BACKGROUND ART Forming fiber reinforced mats into useful shapes is very well known. Such formation is usually relatively simple and is formed by placing the mat in a heated matched die mold having the desired final shape and adding a matrix resin. The production of continuous strand mat usually involves the application of a thermoset polyester adhesive material to the continuous strand.

At present, an improved process for the production of mats capable of preforming continuous strands which is particularly useful for further casting operations has been invented.

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a preformed continuous strand mat. The present invention involves the use of a heat-softening adhesive system in which continuous strand mat can be easily formed into a suitable preform. Also, according to the present invention, an improved preformable continuous strand mat formed by the method of the present invention comprising an adhesive matrix comprising both a thermoset polyester adhesive material and a thermoplastic adhesive material. I will provide a.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a pre-formed continuous strand mat using a heat-softenable adhesive system. The invention further relates to a "preform" of continuous strand mat.
The mat may be heated in an oven or by a heat lamp and bent or pulled to form the desired shape using a forming screen or mold. After molding, the mat is cooled and the molding or preform can be handled in the next casting operation.

The present invention relates to the formation, size, and siz of bushings used today to manufacture strand mats.
ing) and a size application process, and is suitable for practical use.

The adhesive matrix material is applied to the continuous strand mat using a traditional powder applicator. In a preferred embodiment, the adhesive content is
It ranges from about 3.5 to about 6.5 percent. The adhesive material is a combination of a thermosetting polyester adhesive material and a thermoplastic polyester adhesive material. In comparison,
Prior art continuous strand mat production method is 100%
The use of thermosetting adhesives and 100% thermoplastic adhesives today, the chopped strand boat mat (ch
Used in the manufacture of opped strand boat mats).

One suitable preformable mat made according to the present invention is 80% thermoplastic polyester adhesive material and 20%
Adhesive Matrix of the thermosetting adhesive is used. Adhesive ratio from about 90% thermoplastic / 10% thermoset to about 50%
It should be noted that it can vary up to% thermoplastic / 50% thermoset. In a preferred embodiment, the ratio is approximately 80% thermoplastic adhesive material to 20% thermoset adhesive material.

In accordance with the present invention, the mat containing the adhesive matrix material is heated to cure and harden the thermoset polyester adhesive while the thermoplastic polyester adhesive softens and becomes stranded. Intersections
section). When the heat is removed, the mat cools and the thermoplastic polyester adhesive portion of the adhesive mixture solidifies.

The cooled thermoplastic and the cured thermoset adhesives provide the mat with the necessary additional handling for packaging and subsequent handling by the consumer. After passing the mat through a cooling section,
The mat is then passed through a set of compaction rollers. The gap is
When the mat is processed in a casting operation, it is wide enough not to bind the mat tightly to prevent damage to the mold, but contains glass (beads or chips)
Small enough to break. In a preferred embodiment, the gap is fixed at approximately 0.080 inches.

The mats formed according to the present invention are particularly useful for the casting of automotive bumpers, as the majority of the casting time can be spent on placing the mat in the mold. The mat must be placed in the mold, usually by hand, and pressed into corners and curves. The mat formed on a flat conveyor retains its flat "memory", resists bending for forming, and often jumps out of a mold or curve of the desired shape. On the other hand, the preformable mat formed according to the present invention, when fixed in the desired shape, retains that shape and does not pop out of the mold or curve of the desired shape.

Further, the mats of the present invention may be heated in a heat lamp or a low temperature oven, which reduces energy and the cost of major equipment required in other pre-forming steps.

In accordance with the present invention, the pre-drying heat is turned off and the pre-drying fan is turned off to maintain a maximum moisture of 10-35%, which is preferred to retain the adhesive particles. A similar moisture retention cure is achieved by tacky sizing during molding.
g) and reducing the water content to 3-7% using heat and air flow from the pre-dried fan.

Further, preforms made from preformable mats formed according to the present invention are stacked.
d) Alternatively, it may be handled by robots or mechanical equipment, thereby reducing the labor required for mold loading or handling of preforms for shipping on ships. To reduce.

Yet another advantage of the present invention is that the advantage of using a thermoplastic adhesive in the adhesive matrix allows for the production of preforms having more complex shapes and deeper "draws". is there.

Changing the sizing method to a sizing method that has sufficient tenacity to hold onto the adhesive matrix material during curing, but at the same time does not result in a continuous strand mat that is too hard to preform is a book It can be used with the method of the invention. If a higher content of adhesive matrix material is required, the use of finer split shoes can be used to improve the adhesive pick-up on the mat.

The preform was heated by heating the mat to above 200 ° F (93.3 ° C), placing the mat in a cold mold, and closing the mold to form the shape of the mat, solidifying It was manufactured by letting it. In some embodiments, the mat is heated from about 176 ° C to 193.3 ° C (350 ° F to 380 ° F).
Heat to a temperature between The method of the present invention provides a relatively thick continuous strand mat that can be compressed into a thin shaped shape having sufficient strength for good handleability.

Industrial Applicability The automotive industry gives the preforms of the invention a particularly useful position. Preforms can have more complex shapes and deeper dents due to the advantages of using a thermoplastic adhesive. This is especially true for truck
Useful for shaping complex automotive parts such as cabs).
Flat mats formed on flat conveyors retain flat memory and resist bending and forming. The mat often jumps out of the mold or curve of the desired shape.
After molding, the mats of the present invention retain their shape and the operator can handle them in subsequent casting operations.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29B 11/16 B29B 15/08-15/14 B29C 70/00-70/88 C08J 5/24 C08J 5 / 04-5/10

Claims (4)

(57) [Claims] 1. The method of claim 1 wherein the thermosetting polyester adhesive material and the thermoplastic polyester adhesive material are combined to form an adhesive matrix material, wherein the matrix material comprises from 10% to 50% by weight of the matrix material. 90% of matrix material per weight of matrix material
From about 50% of a thermoplastic polyester adhesive material; applying the adhesive matrix material to a continuous strand mat; placing the continuous strand mat in a mold and subjecting it to 93.3 ° C.
By heating to a temperature above (200 ° F.) and closing the mold to form a mat and solidifying, the thermoset adhesive material cures and hardens;
On the other hand, the thermoplastic adhesive material softens and flows near the intersections of the strands of the continuous strand mat; thereafter, the continuous strand mat is solidified to solidify the thermoplastic polyester material of the adhesive matrix material. Cooling, forming a cold mat; and widening the cold mat wide enough not to bind the mat tightly, but narrow enough to break the glass content present in the continuous strand mat. A set of compaction rollers set
For forming a preformable mat of continuous strands having glass contacts and strand contacts consisting of passing through. 2. The method of claim 1 wherein said adhesive matrix material is present in a ratio of 80% by weight of thermoplastic polyester adhesive material to 20% by weight of thermoset polyester adhesive material. . 3. Heating the mat to a temperature between 176.6.degree. C. to 193.3.degree. C. (350.degree. F. to 380.degree. F.) to cure and harden the thermoset adhesive material while the thermoplastic adhesive material 2. The method of claim 1 wherein the softening flows and flows near the contact points of the strands of the continuous strand mat. 4. The method of claim 1 wherein said thermoplastic polyester adhesive material comprises 20
2. A continuous strand mat produced by the process of claim 1 which is present in a proportion of 80% by weight, based on the weight of thermosetting adhesive material.