JPS602422B2 - Method for manufacturing glass fiber matte - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a glass fiber mat, and an object of the present invention is to obtain a glass fiber mat suitable for reinforcing FRP.

Chopped strand mats (abbreviated as CM) and continuous strand mats (abbreviated as CSM) are known as glass fiber mats for reinforcing FRP.

CM is the most widely used mat for FRP and is manufactured using cake as a starting material.

A cake is a large number of glass fibers pulled out from a bushing, which are added with a concentration agent and concentrated to form glass fiber strands, which are then traversed onto a paper tube placed on a mandrel that rotates at high speed. Well, it's rolled up. The cake is usually sent to a heating furnace to heat it and harden the topping agent before being sent to the next step. A large number of cakes are arranged in parallel, a strand is pulled out from each cake, sent to a cutting device, cut into a predetermined length, and deposited on a conveyor that moves the cut strands (chopped strands).A binder is applied and heated, and the chopped strands ( CS
(abbreviation)) are glued together to form a CM. The length of the CS is usually about a few feet long, and sometimes it is about 10~1& or so long.
S is also used. In addition, a large number of strands pulled out from a cake may be rolled up into a roving and cut into a cylindrical shape to form a CS.

CM is inexpensive and suitable for mass production, and is widely used for reinforcing FRP.

When CM is used for hand lay-up, it conforms well to the mold and is easy to work with. However, this is because the CM stretches locally when a force is applied to it, which has the disadvantage that the strength of the stretched section decreases, and when deep drawing is performed, the deep drawn section breaks. . CSM applies a concentration agent to a large number of glass fibers drawn from a bushing, collects them into a strand, brings this strand into contact with a wheel presog rotating at high speed, pulls it, and shakes it off.
It is manufactured by depositing it in a loop on a moving conveyor, applying a binder, and heating it to bond the strut lands together.

The strands that make up CSM are continuously looped, so when CSM is used to reinforce FRP, the mat is partially stretched during the molding process, resulting in a localized strength loss, unlike when using CM. FRP with high strength can be obtained without the occurrence of cracks, and CSM has the advantage of good conformability to molds and does not break even when deep drawing is performed.

However, CSM is more expensive than CM, has less demand, and has a large production volume per production facility, making it difficult to produce a wide variety of products. Now, the following restrictions arise. As mentioned above, CSM is manufactured by collecting the glass fibers ejected from the bushing and depositing them on a moving conveyor.

The thickness of the drawn glass fiber decreases as the drawing speed increases, and in order to obtain glass fibers with a suitable thickness (about several to tens of #s), the drawing speed of the glass fiber should be adjusted. (The pulling speed by the pulling wheel needs to be 1000 to 2000 min.) On the other hand, the moving speed of the conveyor is determined by the amount of strands that should be deposited per unit area of the conveyor, but there are also mechanical constraints, so it is usually Therefore, since the drawing speed of the glass fiber is extremely high compared to the moving speed of the conveyor, the glass fiber east forms a loop shape with a small radius on the conveyor. It is deposited in a state of

On the other hand, the strand wound as a cake is tightly wound onto a paper tube and wound one after the other, so it is crushed and flattened with a ratio of major axis to minor axis of about 10:1 to 2:1. However, the strand produced by the wheel pulling method is simply shaken off by contacting the surface of the rolling wheel, and therefore is not crushed and has a substantially circular cross section. As mentioned above, in CSM, the strands with a circular cross section form a loop shape with a small curvature, and the loops overlap with each other with a slight deviation, so the rebound force against compression is large, and therefore, compared to CM. It is difficult to increase the amount of glass fiber per unit volume, and this tendency is particularly remarkable in the hand lay-up method. (Incidentally, the amount of glass fiber per unit volume is a major factor in improving the properties of FRP, such as tensile and bending strength, and the inability to increase the amount of glass fiber is a major negative factor for reinforcing materials. ) As a result of repeated research to solve these difficulties and obtain a reinforcing material with a large amount of glass fiber per unit volume while retaining the excellent properties of CSM, the present inventor pulled out the wound glass fibers. The present invention has been proposed based on the discovery that extremely favorable results can be obtained by cutting the glass fabric into lengths of one or more lengths, applying a binder, stacking them, and adhering the cut pieces of glass fabric to each other.

Next, the present invention will be specifically explained.

A large number of glass fibers with a diameter of about 9 to 18 mm are pulled out from a bushing, are added with a sizing agent, are concentrated, and are wound up while being traversed on a paper tube inserted with an iron on a mandrel rotating at high speed.

The number of bags is approximately 50 to 200, and the winding speed is 1000 to 200.
It is about 2000 skin'min. 13 pieces of the resulting cake
After heating at 0° C. for about 5 hours to sufficiently harden the bag toning agent, the glass fiber strands are taken out from the cake and cut into lengths longer than the length of drawer 1, and deposited on a moving conveyor with a binder applied thereto. The glass fiber mat of the present invention can be continuously produced by heating and adhering the cut glass fibers to each other. There are no particular restrictions on the binder, but
Liquid castle is finely powdered polyester resin emulsion, epoxy resin emulsion, vinyl acetate resin emulsion ~ acrylic resin emulsion, ethylene vinyl acetate copolymer emulsion, polyester alkyd resin powder,
Suitable results can be obtained using epoxy resin powder, novolak powder, etc.

The amount of binder used is about 2 to 1% by weight as a solid substance based on the glass fiber strand. According to the method of the present invention, the glass fibers are drawn out after being wound once, so that the thickness of the glass fibers can be maintained at an optimum value and the drawing speed can be greatly reduced.

Moreover, when using the method of the present invention, the glass fibers are cut and polished without being continuously polished on the conveyor, so that the glass fibers deposited on the conveyor can be obtained by the wheel pulling method. Unlike CSM, which has a small radius of curvature and does not form loops with slightly shifted positions, the glass fibers are randomly deposited in a loosely bent state with a large radius of curvature, as will be described later. Ru. Furthermore, the glass box side openings used in the present invention are flat because they are pulled out after being rolled up. Therefore, it is possible to shrink the material to a higher bulk density than conventional CSM. This effect is particularly remarkable in the hand layup method. The CS that makes up the CM is arranged almost linearly in no direction, and in FRP that uses CM as a reinforcing agent, the mat partially stretches during the molding process, resulting in a localized decrease in strength. Therefore, its strength is lower than that of FRP using CSM, and it cannot be deep drawn.

The inventor of the present invention attempted to increase the length of the CS beyond the conventional range of commercials, and as a result obtained the following knowledge.

When the length of CS is short, CS is linear, but C
When the length of S becomes large, the CS is arranged in a gradually curved manner. The relationship between the length of the CS and the degree of curvature varies depending on the thickness of the CS, etc., but in general, when the length of the CS exceeds 60 arcs, it begins to curve considerably, and the deep drawability of the resulting mat improves.
When the length is lm or more, a mat with a large curvature and randomly distributed curved loops is obtained, and this mat has a uniformity of strength and "deep drawability" that is comparable to that of conventional CSM. It was found that the mat obtained by the method of the present invention does not partially stretch during the molding process and cause a local decrease in strength, and is superior to conventional CSM. It has comparable strength uniformity and deep drawability, and can be made to a high density even in hand lay-up.Furthermore, when the method of the present invention is used, the mat can be produced in large quantities and has various properties. The starting material is a cake that has been produced in many different types, and can be manufactured using conventional CM manufacturing equipment, so many different types can be manufactured without using special equipment.

In addition, in the conventional pulling IJ method, depending on the type of pulling agent added to the glass fibers, there is a risk that the pulling agent may adhere to the cylinder (pulling wheel) rotating at high speed and obstruct the work. Even when the use of certain binding agents (e.g. vinyl acetate or acrylic emulsion) is desirable due to the properties that should be imparted to the mat, it has been necessary to refrain from using them in order to facilitate the work. , the method of the present invention has the advantage that such constraints do not exist at all.

Next, examples of the present invention will be shown.

Example 100 glass fibers with a thickness of 13A pulled out from a bushing were added with a vinyl acetate-based concentration agent, wound on a paper tube rotating at high speed to form a cake, and heated at 130 pm for 5 hours. did.

From this cake 23 strands, 400'
Pull it out at a speed of min, cut it to 1.5 skin length, and
The strands were deposited on a conveyor moving at a speed of 45 mm/mm to obtain a mat in which strands bent to a curvature of 20 mm were randomly distributed. Using this mat and impregnating it with unsaturated polyester resin, it was possible to easily cover FRP with a glass content of 40% by hand lay-up. The bending strength of this FRP was 30k9'm, and the tensile strength was 17kg/boiled, and the FRP strength was uniform with no directionality. Further, the deep drawability of the mat was comparable to that obtained by the wheel pulling method. In addition, when FRP is manufactured by hand-laying using conventional CSM, it is difficult to obtain FRP with a glass content of 25% or more, and the bending strength is 16k9' and the tensile strength is 8k9.
' It was.

Claims (1)

[Claims] 1. A method for manufacturing a glass fiber mat, which comprises pulling out a wound glass fiber bundle, cutting it into lengths of 1 m or more, adding a binder, depositing the bundle, and bonding the cut glass fiber bundles together by heating. .