JPH10258424A - Glass fiber reinforced polypropylene resin and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent product at low cost by a method wherein a carboxylic acid, a dicarboxylic acid or their anhydrides, the rate of each of which to a polypropylene is specified and a specified rate of an organic peroxide to the polypropylene are fed through a main supplying port, while glass fiber chopped strands are fed through a second supplying port. SOLUTION: A two stage type twin-screw extruder is used. The ratio of a polypropylene and modified polypropylene mixture fed to a first stage and a glass fiber fed to a second stage is selected arbitrarily. As a carboxylic acid, a dicarboxylic acid or their adhydrides used for modification, normally a maleic acid anhydride is used. The loadings of an organic peroxide is set to be 0.01-0.2 pts. to 100 pts. of polypropylene. In addition, the glass fibers are fed in the shape of chopped strands. As a carboxylic anhydride, 0.05-1.0wt.% of which is added to polypropylene. As a result, a glass fiber reinforced polypropylene excellent in physical properties can be manufactured and that excellent in cost can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a glass fiber reinforced polypropylene resin which is inexpensive and has excellent mechanical strength and a method for producing the same.

[0002]

2. Description of the Related Art Glass fiber reinforced polypropylene resin is
Since it is an inexpensive material having excellent mechanical strength, heat resistance, moldability, etc., it is used for various industrial parts. In particular, since glass fiber reinforcement improves mechanical properties such as strength and rigidity, its use is expected to be expanded to the extent that so-called engineering plastics are used.

[0003] However, the basic problem of polypropylene in reinforcing short fiber glass fibers is that even if glass fibers are surface-treated with a silane coupling agent, they have little adhesion to polypropylene. The glass fiber interface peeled off and could not play a role of transmitting force.

[0004] For this reason, it has been practiced to incorporate a polypropylene modified by introducing a polar group such as a carboxyl group into the polypropylene. The modified polypropylene is generally produced by a method of reacting maleic anhydride with polypropylene in a molten state.
The polypropylene modified with 0% by weight of maleic anhydride is mixed with polypropylene in a ratio such that the amount of maleic anhydride becomes 0.05 to 0.2% by weight, and glass fibers are blended with the mixture and extruded. It is for producing fiber reinforced polypropylene compounds.

In this case, a mechanism (principle) for improving strength is adopted.
However, as shown in FIG. 2, the phase (layer) of the fully modified polypropylene molecule 22 is chemically bonded to and surrounds the glass fiber 21, and the surrounding is further partially surrounded by the phase of the unmodified polypropylene molecule 23. It is said that the material is surrounded while being melted, whereby good interfacial adhesion between the polypropylene and the glass fiber is obtained.

[0006]

However, in such a method, the mechanical strength of the obtained glass fiber reinforced polypropylene is not yet sufficient. Further, in order to sufficiently graft the carboxylic acid and the like, the required reaction time becomes longer, and therefore, in order to produce such polypropylene, by a reaction by a solution method, or in order to produce an acid-modified polypropylene, It is necessary to use a special twin-screw extruder. Furthermore, since a modified polypropylene produced in a separate step and produced in a small amount is used, the cost is inevitably high. Furthermore, the molecular weight is reduced by the cleavage of the polypropylene main chain by the graft reaction, which lowers the strength of the compound.

Furthermore, since the modified polypropylene is inevitably exposed to air for producing pellets at a high temperature, the product is colored, albeit slightly. Therefore, development of a glass fiber reinforced polypropylene which is excellent not only in mechanical strength but also in price and aesthetic appearance and a method for producing the same are desired.

[0008]

Means for Solving the Problems The inventors of the present application have made intensive studies to solve the above-mentioned problems, and as a result, have found the following facts, thereby completing the present invention. First of all, even if fully modified polypropylene is not mixed with unmodified polypropylene, even if the degree of modification as a whole is the same, the effect of glass fiber reinforcement is the same even with uniformly modified polypropylene. .

[0009] For this reason, polypropylene having a large degree of modification strongly adheres to the glass fiber, so that its molecular movement is hindered, and this interfacial phase becomes brittle, and consequently stress concentration occurs with the unmodified polypropylene phase. It seems that such a phenomenon does not occur if the whole is uniformly denatured.

[0010] Next, under the above conditions, the entire polypropylene is uniformly dispersed at 0.05 to 1.0% by weight, preferably 0.05 to 0.1% by weight.
If it is modified with 5% by weight, more preferably 0.1 to 0.2% by weight of carboxylic acid or dicarboxylic acid, it can be produced using a usual extruder.

Secondly, even if an attempt was made to carry out acid modification using a conventional extruder, a modified polypropylene having a low grafting efficiency and a high adhesive effect could not be produced. In order to prevent oxidation during high-temperature processing or use at high temperatures, and to prevent deterioration due to this, an antioxidant is included. Due to the action of this antioxidant, radical polymerization of polypropylene is significantly initiated by peroxide. This is because it is delayed or suppressed. In the present invention, however, the polypropylene is not denatured at a high concentration, but the polypropylene is denatured at a low concentration and the whole is uniformly denatured. %, It is possible to carry out acid modification sufficient for the purpose. In addition, an excellent product can be manufactured at low cost as compared with a glass fiber reinforced product blended with a highly modified polypropylene according to a conventional technique.

Specifically, the configuration is as follows. In the first aspect of the invention, the first stage has a kneader type and / or
Alternatively, a method of producing glass fiber reinforced polypropylene using a disk-type kneading mechanism and a twin-screw extruder having a disk-type kneading mechanism in the second stage, wherein the polypropylene is supplied from the upstream main supply port to the polypropylene. 0.
A raw polypropylene modified raw material supplying step of supplying 0.5 to 1.0% by weight of a carboxylic acid or a dicarboxylic acid or an anhydride thereof and 0.01 to 0.5% by weight of an organic peroxide, and a second downstream supply port And a glass fiber supply step of supplying a glass fiber chopped strand from a glass fiber reinforced polypropylene resin.

According to the above construction, glass fiber reinforced polypropylene is produced using a twin-screw extruder having a kneader type and / or disk type kneading mechanism in the first stage and a disk type kneading mechanism in the second stage. Is done. At this time, the content of the polypropylene is 0.05 to 1.0% by weight, preferably 0.05 to 0.5% by weight, more preferably 0.1 to 0.5% by weight.
It is uniformly modified with 2% by weight of carboxylic acid and the like, and good interfacial adhesion to glass fibers is obtained. Next, the glass fiber chopped strand is forcibly supplied from the second supply port on the downstream side of the extruder. Under this condition, uniform mixing of the modified polypropylene and the glass fiber is performed downstream of the extruder, but since all of the carboxylic acid is consumed for the modification of the polypropylene, the subsequent processing steps and molded products of the glass fiber reinforced polypropylene There is no adverse effect on the use of. Also, the glass fibers are not damaged due to excessive mixing.

According to the second aspect of the present invention, the second aspect is provided.
The polypropylene used in the invention of the present invention does not contain an antioxidant or contains an amount which influences the oxidation reaction of the polypropylene with an organic peroxide, that is, at most 0.1% by weight, preferably 0.05% by weight. % Or less. According to the above configuration, the modification of the polypropylene is satisfactorily performed even in the extruder.

According to the third aspect of the present invention, the second aspect is provided.
Alternatively, the carboxylic acid or the like used in the third invention is maleic acid or maleic anhydride. According to the above configuration, maleic acid or the like, which is inexpensive and has an excellent denaturing effect, is used, so that the cost is further reduced and the quality is further improved.

According to the fourth aspect of the present invention, the first aspect is provided.
In the invention according to claim 3, further, when supplying the glass fiber chopped strand from the second supply port,
At the same time, it has an additive supply step of appropriately supplying additives such as an antioxidant due to aging or high temperature during use, and other additives such as light stabilizers, lubricants, release agents, and coloring agents. I have. According to the above configuration, an additive for improving various performances of the glass fiber reinforced polypropylene is added to the modified polypropylene which has been modified and has no free carboxylic acid or the like, in addition to the glass fiber. Therefore, there is no adverse effect of the carboxylic acid on the additive.

According to the fifth aspect of the present invention, 0.05
To 1.0% by weight, preferably 0.05 to 0.5% by weight,
More preferably, it is a glass fiber reinforced polypropylene uniformly modified with 0.1 to 0.2% by weight of carboxylic acid or dicarboxylic acid or an anhydride thereof. According to the above configuration, good interfacial adhesiveness between the polypropylene and the glass fiber without stress concentration is obtained, so that a glass fiber reinforced polypropylene excellent in strength can be obtained.

[0018]

Embodiments of the present invention will be described below. First, the extruder will be described. In the process of the present invention, a two-stage twin screw extruder is used. This can take a variety of forms, but the most suitable is the overall L /
D is 30 or more, L / D of the first stage is 20 or more, at least 5 or more of which are kneading blocks, and L / D of the second stage is 10 or more and at least 5 of them. The above is composed of disk-type distributed blocks.

FIG. 1 shows an example of the schematic mechanism. In order to stabilize the grafting reaction, it is preferable to replace the inside of the cylinder with an inert gas such as nitrogen. Equipment for this is provided, but this is not shown because it is a well-known technique. Similarly, a vent hole is provided in the latter half of the second stage, and equipment for sucking and removing moisture and gas components under reduced pressure is also provided, but not shown in the drawing.

The ratio of the polypropylene and modified polypropylene mixture supplied to the first stage and the glass fiber supplied to the second stage can be arbitrarily selected from 80/20 to 40/60 depending on the purpose of the blend. Similarly, a vent hole is provided in the second half of the second stage, and it is preferable to suction and remove moisture and gas by reducing the pressure. Therefore, such equipment is also provided, but this is also omitted from the drawing.

Next, the raw materials will be described. Although it is polypropylene, either a homopolymer or a block copolymer is used depending on the purpose of use of the final product. That is, when it is desired to increase tensile strength or rigidity, a homopolymer is used, and when impact resistance is required, a block copolymer is preferably used.

In the present invention, as the form of polypropylene, pellets may be used, but granular polypropylene having a particle size of 1 mm or less is most preferable. As such polypropylene, a granular material having an average particle size of 0.6 to 0.7 mm is commercially available, and this is most preferred. However, the present invention is not limited to this.

Although unpelletized products after polymerization can be used, they contain a large amount of fine particles having a particle size of 100 μm or less, so that dust is likely to be generated, which is not only unfavorable in working environment but also may cause dust explosion. It is preferable to add an appropriate wetting agent to such a raw material. Such wetting agents include, but are not limited to, sodium alkyl naphthalene sulfonate, polyoxyethylene sorbitan monolaurate, polyethylene glycol, glycerin, liquid paraffin, and the like.
Next, from the viewpoint of the material of the polypropylene, it is naturally preferable that no antioxidant is contained.

The carboxylic acid, dicarboxylic acid or anhydride thereof used for modification is usually maleic anhydride because of its bifunctionality and low cost. Here, the reason why the anhydride is used instead of maleic acid is that monomer reactivity is high and grafting is easy in terms of steric hindrance and polar factors. In addition, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, citraconic anhydride, itaconic anhydride and the like can be used.

The organic peroxide has a decomposition temperature of 150 ° C. to 250 ° C., preferably 160 ° C. to 1 ° C. for a half-life of 1 minute.
80 ° C. can be used. These include lauroyl peroxide, benzoyl peroxide, ditertiary butyl peroxide, tertiary butyl perbenzoate, dicumyl peroxide, 1,3 bis (t-butylperoxyisopropyl) benzene, etc.
It is not limited to these.

Organic peroxides having a decomposition temperature lower than 150 ° C. decompose and lose their effect before the polypropylene melts, and organic peroxides having a decomposition temperature higher than 250 ° C.
It cannot work within the residence time in the cylinder of the injection molding machine, and there is no opportunity for a hydrogen abstraction reaction from the polypropylene. That is, in each case, the degree of acid modification of the polypropylene is low, and the effect is low.

The organic peroxide may be used in the form of a powder or a liquid. However, the organic peroxide is preferably a liquid in that it can be uniformly blended, but may be volatilized before being decomposed. Therefore, a powder having a high boiling point is more preferable. The powdered powder may cause an explosion if it is used. Therefore, from the viewpoint of preventing the danger of work, it is preferable to use a master batch in which 50 to 80% by weight is mixed with paraffin wax or inorganic powder. However, in this case, it is a necessary condition that the particle size of the master batch is equal to or smaller than that of polypropylene.

The compounding amount of the organic peroxide is 0.01 to 0.2 part based on 100 parts of polypropylene. If the amount is less than this, the acid modification becomes insufficient, and if it is more than this, the molecular weight of the polypropylene decreases and the strength of the product is impaired.

The glass fiber is usually E-glass having a diameter of about 10 μm (in the range of about 5 to 15 μm in terms of breaking resistance or the like) and a length of about 3 to 6 mm, and the surface is made of modified polypropylene. In order to further improve the interfacial adhesion, it is preferable that the material is previously treated with a silane coupling agent. In addition, as a silane coupling agent, amino silane, epoxy silane, and acrylic silane are usually used.

Further, in order to converge the glass fibers, polyurethane, epoxy resin or the like is used as a film former. Then, several hundred to one thousand glass fibers converge and are supplied in the form of so-called chopped strands, which are cut into about 3 mm (approximately in the range of 2.5 to 3.5 mm). If the glass fiber is too long, the dispersibility decreases, which is not preferable. If the glass fiber is too short, it is not preferable in terms of handling, product strength and the like.

Regarding the compounding ratio of each raw material, the compounding ratio of polypropylene, carboxylic acid and organic peroxide is such that if the amount of modification of the polypropylene with an acid is too small, it is not possible to obtain proper adhesion to glass. Even if too much, there is a limit to the improvement of the adhesiveness as well as the molecular weight of polypropylene decreases,
The strength of the composition decreases. Generally, the carboxylic anhydride is from 0.05 to 1.0% by weight, preferably from 0.05 to 0.5% by weight, and even more preferably from 0.1 to 0.2% by weight of the polypropylene. % By weight.

Next, from the second stage, additives such as an antioxidant, a light stabilizer, a carbon black conductive agent, a flame retardant, a lubricant, a release agent, and a coloring agent may be supplied together with the glass fibers. These are supplied in a pre-blended form with the glass fibers or directly from another metering device to the second supply port. Further, they may be supplied in the form of respective master batches. The additive chemically inert to carboxylic acid or peroxide may be supplied from the main supply port.

Further, a filler which is conventionally often blended with polypropylene can also be blended. These include calcium carbonate, talc, clay, mica, wollastonite, etc., which can be used for secondary
It can also be supplied from the supply port.

[0034]

The present invention will be specifically described below with reference to examples and comparative examples. Processing machine Kneading extruder: NRII-46mm SG twin screw extruder manufactured by Freesia Macross Co., Ltd. Cylinder temperature 250 ° C. Screw rotation speed 300 rpm L / D = 40 First stage L / D = 24 Inner kneading block 6.5 Second stage L / D = 16 Inner kneading disk 4.0 Incidentally, FIG. 1 shows the configuration of the kneading extruder of this embodiment and how raw materials are supplied in this embodiment.

Raw materials: Polypropylene PN640 manufactured by Tokuyama Corporation Fine particles containing a small amount of antioxidant (roughly 0.05 to 0.1% by weight) MS640 manufactured by Tokuyama Corporation Pellet containing antioxidant (approximately 0.1% by weight) BJHH-P manufactured by Mitsui Toatsu Co., Ltd. Fine particles containing a small amount of antioxidant (approximately 0.05 to 0.1% by weight) BJHH-1352 pellets manufactured by Mitsui Toatsu Co., Ltd. Contains antioxidant (approximately 0.1 to 0.2% by weight)

[First Embodiment] In this embodiment, a glass using a glass fiber reinforced polypropylene of the prior art, that is, a polypropylene obtained by mixing 1/3 to 1/5 of a fully modified polypropylene with unmodified polypropylene is used. The present invention relates to a strength comparison between a fiber reinforced polypropylene and the glass fiber reinforced polypropylene of the present invention, that is, a glass fiber reinforced polypropylene using a uniformly modified polypropylene having the same degree of modification as the conventional one.

In Example 1, a polypropylene resin (manufactured by
Polypropylene and glass fiber obtained by uniformly modifying 100 parts of Tokuyama PN640) with 0.2 parts of maleic anhydride (primary reagent) and 0.1 parts of peroxide (1.3 bis (t-butylperoxyisopropylbenzene)) 100 parts is a glass fiber reinforced polypropylene produced by using the above-described twin screw extruder, and the cylinder temperature was 200 ° C. as in the comparative examples.

In Comparative Example 1, as described in Reference Example, 100 parts of polypropylene (PN640, manufactured by Tokuyama Corporation) were mixed with 0.6 part of maleic anhydride (primary reagent) and peroxide (1.
3-bis (t-butylperoxyisopropylbenzene)
33 parts of polypropylene modified with 0.1 part (graft ratio: 0.46%), 67 parts of unmodified polypropylene (MS640 manufactured by Tokuyama Corporation) and 100 parts of glass fiber, and glass fiber reinforced polypropylene produced using 100 parts of glass fiber as raw materials. is there.

As shown in Table 1, the strength of the glass fiber reinforced polypropylene of the present invention is not inferior to that of the prior art. In addition, in any of the glass fiber reinforced polypropylenes, poor dispersion of the glass fibers was not observed, and the surface state was smooth.

[0040]

[Table 1]

[Second Embodiment] The present embodiment relates to the effect of the presence or absence of an antioxidant in the raw material polypropylene on the modification of the polypropylene.

Example 1 A. 100 kg of polypropylene resin (PN640, manufactured by Tokuyama Corporation) 200 g of maleic anhydride (reagent first grade) 200 g 1.3 g of bis (t-butylperoxyisopropyl) benzene 100 g / hr was supplied from the main supply port. B. Glass fiber (Central Glass Co., Ltd. ECS03-6)
20) was supplied from the second supply port by a 50 kg / hr side feeder. The extruded strand was water-cooled and cut with a pelletizer to produce a pellet.

Comparative Example 1 A. B. Polypropylene resin (MS640, manufactured by Tokuyama Corporation) 100 kg Maleic anhydride (first grade reagent) 200 g 1.3 Bis (t-butylperoxyisopropyl) benzene 100 g Glass fiber (Central Glass Co., Ltd. ECS03-6)
20) was supplied from the second supply port by a 50 kg / hr side feeder. The extruded strand was water-cooled and cut with a pelletizer to produce a pellet.

Example 2 A. A mixture of 100 kg of polypropylene resin (BJHH-P, manufactured by Mitsui Toatsu Co., Ltd.), 200 g of maleic anhydride (first grade reagent), and 100 g of di-t-butyl peroxide was fed at 50 kg / hr from the main supply port. B. Glass fiber (Central Glass Co., Ltd. ECS03-6)
20) was supplied from the second supply port by a 50 kg / hr side feeder. The extruded strand was water-cooled and cut with a pelletizer to produce a pellet.

Comparative Example 2 A. B. Polypropylene resin (BJHH-1352 manufactured by Mitsui Toatsu Co., Ltd.) 100 kg Maleic anhydride (first grade reagent) 200 g Di-t-butyl peroxide (manufactured by NOF Corporation) 100 g Glass fiber (Central Glass Co., Ltd. ECS03-6)
20) was supplied from the second supply port by a 50 kg / hr side feeder. The extruded strand was water-cooled and cut with a pelletizer to produce a pellet.

Comparative Example 3 A. B. 100 kg of polypropylene resin (BJHH-1352 manufactured by Mitsui Toatsu Co., Ltd.) 2 kg of modified polypropylene (UMEX 1010 (10% water-free maleic acid modified polypropylene manufactured by Sanyo Chemical Industries, Ltd.)) Glass fiber (Central Glass Co., Ltd. ECS03-6)
20) was supplied from the second supply port by a 50 kg / hr side feeder. The extruded strand was water-cooled and cut with a pelletizer to produce a pellet. The obtained glass fiber reinforced polypropylene pellets were molded into test pieces specified by ASTM using an SN75 injection molding machine manufactured by Niigata Ironworks Co., Ltd., and the results of measuring physical properties, particularly mechanical strength, are shown in Table 2 below. Show.

[0047]

[Table 2]

As shown in the table, Example 1 using polypropylene on fine particles containing almost no antioxidant as a raw material,
Comparative Example 2 is superior in mechanical strength to Comparative Example 1 and Comparative Example 2 using pelletized polypropylene containing an antioxidant,
Also, it can be seen that the hue is excellent without coloring. next,
Comparative Example 3 of the prior art has the overall degree of modification of about 0.2%, which is the same as Examples 1, 2 and Comparative Examples 1 and 2, but has the lowest mechanical strength. This is because the degree of modification of polypropylene is 1
Since this is as large as 0%, the modified polypropylene layer becomes brittle when the polypropylene is firmly fixed to the surface of the glass fiber as described above, and is broken by a relatively small external force due to stress concentration at the polypropylene interface. It is.

[0049]

As described above, according to the present invention, it is possible to produce a glass fiber reinforced polypropylene having excellent physical properties by a simpler process than in the case of blending a modified polypropylene by a conventional solution graft reaction. Becomes In addition, since expensive modified polypropylene is not used, the cost is excellent. Further, since the modified polypropylene is not exposed to air during the production of the pellet, coloring of the final product is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of a twin-screw extruder used in the present invention.

FIG. 2 is a diagram conceptually showing a state in which a highly modified polypropylene in a conventional glass fiber reinforced polypropylene is interposed as a binder between glass fiber and unmodified polypropylene.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29C 47/64 B29C 47/64 C08J 3/20 CES C08J 3/20 CESB CESZ 5/08 CES 5/08 CES C08K 5/09 C08K 5/09 5/14 5/14 7/14 7/14 C08L 23/10 C08L 23/10 // B29K 23:00 105: 12 309: 08

Claims (5)

[Claims] 1. A method for producing glass fiber reinforced polypropylene using a twin screw extruder having a kneader and / or disk type kneading mechanism in a first stage and a disk type kneading mechanism in a second stage. From the upstream main feed port, polypropylene, 0.05 to 1.0% by weight of carboxylic acid or dicarboxylic acid or their anhydride, and 0.01 to 0.5% by weight of organic peroxide based on the polypropylene. A method for producing a glass fiber reinforced polypropylene resin, comprising: a supplying step of supplying a modified polypropylene production raw material to be supplied; and a glass fiber supplying step of supplying a glass fiber chopped strand from a downstream second supply port. 2. The method for producing glass fiber reinforced polypropylene according to claim 1, wherein said polypropylene does not contain an antioxidant to such an extent as to affect the oxidation reaction of polypropylene with peroxide. 3. The method for producing a glass fiber reinforced polypropylene according to claim 1, wherein the carboxylic acid or dicarboxylic acid or an anhydride thereof is maleic acid or maleic anhydride. 4. An additive supply for appropriately supplying additives such as an antioxidant, a light stabilizer, a lubricant, a release agent, and a colorant when the glass fiber chopped strand is supplied from the second supply port. 4. The method for producing a glass fiber reinforced polypropylene resin according to claim 1, wherein the method has a step. 5. A glass fiber reinforced polypropylene composition characterized in that the composition polypropylene is substantially uniformly modified by 0.05 to 1.0% by weight.