JPH06287321A - Fiber reinforced plastic material made by using bagasse and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title lightweight an tough plastic material at low cost by using a thermosetting resin, glass fibers and bagasse as the principal constituents at a specified weight ratio of thermosetting resin to bagasse. CONSTITUTION:The material consists mainly of a thermosetting resin preferably comprising an unsaturated polyester, glass fibers, and bagasse preferably comprising a fibrous bagasse crushed to a length of 0.3-20mm at a weight ratio of thermosetting resin to bagasse of at least 2:1, preferably about 3:1. Figure shows the relation between the blending ratio of bagasse an tensile strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced plastic material using sugar cane bagasse as a filler (hereinafter referred to as FR
P) and its manufacturing method.

[0002]

2. Description of the Related Art Most of sugarcane stalks are made of fiber, and the residual rate of bagasse, which is the squeezed residue after molasses squeezing, is very high. (10,000 tons) of bagasse is generated. Traditionally, bagasse is partially used as a material for plywood or lacquer ware, or as fertilizer or feed, but most of it is currently burned as fuel for boilers in sugar factories, and the amount of bagasse produced in large quantities is two. It is hard to say that it is effectively used as the next resource. Therefore, in order to increase the added value of sugar cane, highly effective use of bagasse is required.

On the other hand, molding of glass fiber reinforced plastic (FRP), which is a mixture of thermosetting resin such as unsaturated polyester resin or epoxy resin and glass fiber, is known by various molding methods such as hand layup method and premix method. However, an injection molding method similar to that of thermoplastic resin is known as a molding method capable of being automated and molding a complicated small article.
In the case of the injection molding method, a thermosetting resin, glass fiber, a filler, and other additives are mixed in advance to form a block molding compound (hereinafter simply referred to as BMC), which is injection molded. Conventionally, calcium carbonate has been mainly used as a filler, but the molded FRP has a large specific gravity.
The product is relatively heavier than other plastic products, and there is a problem that an FRP product that is light in weight and rich in toughness cannot be obtained. Further, since FRP uses expensive glass fiber as a reinforcing material, it is tough but generally expensive.

[0004]

DISCLOSURE OF THE INVENTION The present invention was conceived in view of the above circumstances in order to achieve high-value and highly effective utilization of a large amount of bagasse discharged, and the conventional bagasse is used. FRP, which is lighter and tougher than the FRP, and uses bagasse obtained by injection molding at low cost
An object is to provide an RP and a method for manufacturing the same.

[0005]

Means for Solving the Problems In the course of various studies on effective use of bagasse, the present inventor is a hard, tough and light vegetable fiber, which has a needle-like shape after crushing, and glass fiber and As a result of continued research paying attention to the fact that it has a similar shape and has the property of being easily entangled with glass fibers, the inventors have found that bagasse can be used as a filler for FRP and arrived at the present invention.

That is, the present invention is mainly composed of a thermosetting resin, glass fiber and bagasse, and the weight ratio of the thermosetting resin to bagasse is twice or more of the thermosetting resin with respect to 1 bagasse, preferably. It is a fiber-reinforced plastic material using bagasse, which is about three times as large. The thermosetting resin used in the present invention is preferably unsaturated polyester, but it is also possible to use an epoxy resin depending on the application. Further, the weight ratio of the thermosetting resin to the bagasse increases the tensile strength as the amount of bagasse increases, but if the thermosetting resin is less than twice the bagasse, the amount of bagasse is too much and the resin is insufficient. However, since it does not sufficiently penetrate into bagasse, it causes a decrease in strength. Further, the bagasse is preferably fibrous bagasse crushed into a length of 0.3 mm to 20 mm. Bagasse has a needle shape similar to that of glass fiber and has a characteristic that it is easily entangled with glass fiber, but if the length is 0.3 mm or less, needle-like shape characteristics cannot be exhibited, and granular behavior is exhibited. If the length is longer than 20 mm, it is difficult for the unsaturated polyester to penetrate into the bagasse, and the cavity of the bagasse remains.
Strength is reduced. The glass fiber reinforced plastic material of the present invention can be obtained by various molding methods such as a hand lay-up method and a premix method, which are conventional FRP material molding methods. It is possible to obtain a glass fiber reinforced plastic product that can be automated, can efficiently mold even a complicated small object, and is light, durable and inexpensive.

The method for producing a fiber-reinforced plastic material using bagasse of the present invention is mainly composed of a thermosetting resin, glass fiber and bagasse, and the weight ratio of the thermosetting resin to bagasse is 1 bagasse. Then, each component was blended so that the amount of the thermosetting resin was 2 times or more, preferably about 3 times, and the mixture was kneaded for 3 to 4 hours to obtain BMC, and the BMC was injection-molded to use bagasse. It is characterized in that a fiber-reinforced plastic molded product is obtained. If the kneading time is shorter than 3 minutes, it is not enough to impregnate the liquid thermosetting resin into the bagasse, and if it is longer than 4 hours, the glass fiber will be damaged, so the thermosetting resin will penetrate the bagasse sufficiently. A range of 3 minutes to 4 hours is required. More preferably, it is 210 minutes.

[0008]

[Action] Bagasse has a bundle shape when discharged at a sugar factory, but when crushed by a crusher, it changes into a needle shape, which is very similar to glass fiber. This indicates that the bagasse and the glass fibers are compatible with each other during kneading, that is, it is advantageous for entwining the glass fibers. On the other hand, each bagasse cross section has a honeycomb shape when observed with an electron microscope, and it is recognized that the ratio of the cavity portion is about 75% in area ratio. Therefore, the point is how to infiltrate the thermosetting resin into the honeycomb-shaped cavity of bagasse and then to cure it. In fact, when observing the state of the fracture surface of the molding material with high tensile strength and the molding material with low tensile strength with an electron microscope, when the strength is low, the bagasse fiber and the glass fiber are dispersed individually, and the cavity inside the bagasse remains the same. It exists in a state, and it is presumed that the portion acted as a defective portion in the tensile test.
On the other hand, when the tensile strength was high, it was confirmed that the bagasse fiber and the glass fiber were sufficiently compatible with each other and that the thermosetting resin had sufficiently penetrated into the bagasse. Regarding the bending strength, there was not much change between the case where the bagasse fibers were 6 to 10 mesh long fibers and the case where the bagasse fibers were 28 to 35 mesh short fibers.

In order to allow the thermosetting resin to sufficiently penetrate into the honeycomb-shaped cavity of the bagasse, the thermosetting resin needs to be in a sufficient amount to fill the cavity of the bagasse, and the cavity of the bagasse. It is necessary to have a length of bagasse so that the thermosetting resin can easily permeate thereinto, and further, a kneading time for sufficiently permeating into the cavity. In order to study the factors that affect the tensile strength of the molding material in BMC injection molding,
With the injection pressure kept constant, three factors, kneading time, mold temperature, and mold holding time, were taken as factors of the molding conditions that affect the tensile strength, and as a result of the F-test by the experimental design method, all of the factors were significant. , The contribution rate of each factor is the highest, the kneading time is 67.30%, and the die holding time is 18.
44% and mold temperature continue to 10.16%. Also,
The mold temperature and holding time interact with each other, and BMC
It is effective for strength to shorten the holding time when the mold temperature is low and to shorten the holding time when the mold temperature is high, depending on the bagasse content in.

In BCM, bagasse has a bulking material and a viscosity adjusting action as a filler, but it is also useful for improving the strength of the molding material due to the property of easy compatibility with glass fiber,
FRP having higher strength can be obtained as compared with the case where calcium carbonate is used as the filler in the conventional FRP. This means that the amount of expensive glass fiber can be reduced, and the cost of FRP can be reduced. Alternatively, since bagasse is a plant fiber and is light in weight, a lighter weight FRP than before can be obtained.

[0011]

EXAMPLES In the following examples, the raw material components were unsaturated polyester, glass fiber and bagasse as the main components, Vitable Z as the catalyst and zinc stearate as the lubricant. Using a double-arm kneader for the above raw materials, a catalyst is first added to unsaturated polyester for 5 minutes, then a lubricant is added for 5 minutes, a filler is added for 10 minutes, and finally a glass is added. Fiber is gradually added, then 30 minutes to 270
Kneading was performed in the range of minutes to produce BCM. The composition ratio of the components, the roughness of bagasse, the kneading time, and the injection conditions were variously changed. In the following examples, the effects of the blending ratio of bagasse and unsaturated polyester, the shape of the bagasse (fiber length), and the kneading time on the tensile strength were investigated.

Effect of Blending Ratio of Bagasse and Unsaturated Polyester Bagasse is used as a filler in the present invention. In order to know what effect bagasse has on strength, glass fiber and With the other catalysts and lubricants kept constant, the ratios of unsaturated polyester and bagasse were changed as in the following Examples 1-2 and Comparative Example 1, and the tensile strength of the obtained molded pieces was measured. The results are shown in Table 1 and FIG. In addition, in each of Examples 1 to 3, the kneading time was 180 minutes, and the mold temperature was 20.
Injection molding was carried out at 0 ° C., injection pressure of 7.84 MPa and holding time of 3 minutes.

[Table 1] UP: Unsaturated polyester GF: Glass fiber
B: bagasse PBZ: reachable Z SA: zinc stearate As a result, the strength increased as the number of bagasse fibers increased, and the unsaturated polyester / bagasse of Example 2 was 3.04.
In the case of No. 1, the highest strength is shown, but thereafter, the tensile strength is decreased as shown in Comparative Example 1. It is considered that when the amount of bagasse is too large as compared with the unsaturated polyester, the resin is insufficient and the resin does not sufficiently permeate, resulting in a decrease in strength. Further, when the bagasse fiber is small, the viscosity of the BMC is lowered and the molding material has many burrs, resulting in poor quality. However, when the bagasse fiber is large, the unsaturated polyester is sufficiently wetted and impregnated with the bagasse fiber. Good viscosity and good molding material can be obtained. In the example in which the amount of bagasse was 23%, BMC qualitatively showed a string-like viscosity,
It showed the best condition. However, as in Comparative Example 1, 2
On the contrary, when it exceeded 3%, the unsaturated polyester was insufficient for the bagasse fiber, and when it was touched by the hand, it became dry.

Influence of Bagasse Shape Next, in order to investigate the influence of the shape of bagasse on the strength, the crushed bagasse was classified into various meshes by an automatic sieving machine. As a result, the shape of the crushed bagasse can be broadly divided into fibrous material and powder with the mesh # 48 as a boundary, and # 48 to # 200 are powdered bagasse (fiber length is 0.30 mm or less). 6 to # 35 are used as fiber bagasse (0.81 mm or more), paying attention to the shape of each bagasse, various bagasses having different meshes are used, and unsaturated polyester 80.7%, glass fiber 6. 1%, bagasse 12.3%, the same compounding ratio and the same molding conditions were used for molding, and the tensile strength of the molded material was tested.
The result is shown in FIG. As is clear from the figure, the tensile strength of each of the powder bagasse and the fiber bagasse varied within the range shown in the figure, and the intermediate value was confirmed to indicate that the fiber bagasse exhibits about twice the strength of the powder bagasse. . this is,
Considering the packing density, it seems that the powder bagasse is high, but since the glass fiber is directly related to the strength improvement, the fiber bagasse interacts with the glass fiber in a familiar or entangled manner, This is probably because it contributes to the fixation of fibers. On the other hand, the powdered bagasse has a very fine fiber length of 0.3 mm or less, and thus the needle-like shape characteristic of bagasse is not exhibited, and it is considered that the powdered bagasse exhibits a granular behavior.

As described above, it has been clarified that the fiber bagasse is preferably used as the bagasse to be used, but in order to know the optimum value of the fiber length of the fiber bagasse, the fiber length of bagasse is # 28 to #. Short fibers up to 20 (average length about 2.1 m
m), # 14 to # 20 are medium fibers (average length of about 5.3 m
m) and long fibers from # 6 to # 10 (average length 10.8 m
m) and divided into three groups, each having the same mixing ratio (main component UP: 65.5 Wt%, B: 23.0 Wt%, GF: 10.0).
Wt%,) and FRP were molded under the same molding conditions, and the tensile strength of the molded product was measured. The results are shown in the graph of FIG. From the figure, as the fiber length becomes shorter, the tensile strength tends to become stronger. This is because it is difficult for the unsaturated polyester to permeate into the bagasse as the fiber becomes longer, and some hollow portions remain, which causes a decrease in strength. On the other hand, when the short fibers are used, it is considered that the unsaturated polyester sufficiently penetrates to the inside and also plays an effective role in entangling the glass fibers. That is, since the length of the glass fiber after kneading is about 1.8 mm, the length of the glass fiber and the short fiber of bagasse are almost the same, and even if bagasse is entangled with the glass fiber during kneading. It seems to be effective.

[0015] The kneading time effect now, in order to examine the effect of kneading period of time is on strength, was carried out by changing the kneading time. For injection molding, a plunger type horizontal injection molding machine was prototyped and BCM molding was performed.
The molding conditions were such that the injection pressure was 5.9 to 19.6 MPa, the mold temperature was 100 to 200 ° C., and the holding time was 3 to 15 minutes. The influence of the kneading time on the tensile strength depends on, for example, the mixing ratio of the materials such as unsaturated polyester 65.0 wt%, glass fiber 12.0 wt%, bagasse 21.0 wt% and barbutyl Z.
0.5wt% and zinc stearate 1.0wt%,
The relationship between kneading time and tensile strength was investigated. As a result, as the kneading time became longer, the tensile strength of the molding material became higher, and at any molding pressure, the kneading time had a peak value at 210 minutes, but decreased thereafter. This indicates that sufficient time is required to impregnate the bagasse inside with the liquid unsaturated polyester, and further shows that wettability with glass fiber, affinity, and the like are related. However, when the mixture was kneaded for 240 minutes, the strength of the molding material decreased. It is considered that this is because the glass fibers were damaged due to excessive kneading.

Next, the mechanical properties of the BCM according to the present invention using bagasse as the filler thus obtained and the conventional BCM using calcium carbonate as the filler will be compared. Conventional BMC (calcium carbonate 60.0Wt
%, Unsaturated polyester 28.4 Wt%, glass fiber 10 Wt
%) And the glass fiber in the same proportion as in the conventional example are mixed in FIG.
BM according to an embodiment of the present invention using the medium fiber bagasse shown in FIG.
Table 2 shows a comparison of the mechanical properties with C (23.0 wt%, unsaturated polyester 65.5 wt%, glass fiber 10 wt%).

[Table 2] As is clear from Table 2, this example using bagasse as the filler, compared with the conventional BMC using calcium carbonate as the filler, even though the amount of glass fiber as the reinforcing material was the same. It was confirmed that a BMC having a small specific gravity and lightness, excellent tensile strength and Rockwell hardness, excellent chemical resistance, and excellent mechanical properties as compared with conventional ones can be obtained.

[0017]

As described above, according to the present invention, by utilizing bagasse, the strength is not changed or improved as compared with the conventional injection-molded FRP of BMC, and calcium carbonate is used as the conventional filler. It is possible to obtain an FRP having a smaller specific gravity and lighter weight than that of the conventional ones and excellent toughness. Further, since bagasse, which is a slag of sugar cane, is used, a low-cost FRP can be obtained, and highly efficient use of bagasse, which has been mainly used as a fuel in the past, can be achieved. Also,
Since it can be injection-molded, complex shapes can be molded depending on the mold, and it is possible to handle high-mix low-volume or variable-volume production.
Industrial products with high added value can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the blending ratio of bagasse and tensile strength.

FIG. 2 is a graph showing the relationship between the shape of bagasse and tensile strength.

FIG. 3 is a graph showing the relationship between the length of fiber bagasse and the tensile strength.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08K 7/14 KKF 7242-4J C08L 67/06 MSJ 8933-4J 97/02 LSW 7415-4J // B29K 67:00 105: 06 C08L 67:00 8933-4J

Claims (4)

[Claims] 1. A thermosetting resin, glass fiber, and bagasse as a main component, wherein the weight ratio of the thermosetting resin to bagasse is 2 times or more, preferably about 3 times, the bagasse. A fiber-reinforced plastic material using bagasse, which is characterized by being present. 2. The fiber reinforced plastic according to claim 1, wherein the thermosetting resin is an unsaturated polyester. 3. The fiber-reinforced plastic material using bagasse according to claim 1 or 2, wherein the bagasse is fibrous bagasse crushed to a length of 0.3 mm to 20 mm. 4. A thermosetting resin, glass fiber, and bagasse as a main component, wherein the weight ratio of the thermosetting resin to bagasse is 2 to 7 times, preferably about 3 times as much as 1 bagasse. Add each component to the range of 3 to 3 minutes
A method for producing a fiber-reinforced plastic material, which comprises kneading for 4 hours to obtain BMC, and injection-molding the BMC to obtain a fiber-reinforced plastic molded product using bagasse.