JPS60158236A - Polyolefin resin composition - Google Patents

Abstract

PURPOSE:The titled resin composition for molding excellent in strength, rigidity, processability, dimensional stability, etc., prepared by adding a vegetable fiber based on fibrous cellulose to a specified polyolefin resin. CONSTITUTION:The titled composition containing 20-60wt%, based on 100pts. wt. total composition, vegetable fiber based on fibrous cellulose and 40-80wt%, based on 100pts.wt. total composition, polyolefin resin comprising chemically modified polyolefin obtained by adding a carboxylic acid (anhydride) to a polyolefin resin. The total content of the carboxylic acid (anhydride) in the modified polyolefin should be 0.0002-0.0035pts.wt. per above vegetable fiber. This polyolefin resin composition is excellent in strength, rigidity, processability, dimensional stability, etc.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a plant t mainly composed of fibrous cellulose.
The present invention relates to a moldable polyolefin resin composition containing lAM.

[Prior Art] Conventionally, materials prepared by blending inorganic fillers such as talc, calcium carbonate, mica, and glass fiber with polyolefin resins, particularly polypropylene resins, have been well known mainly as materials for injection molding. On the other hand, there are some known materials that are made of polyolefin resin mixed with organic fillers such as wood flour, rice husks, and waste paper, and some of them are in practical use.
Due to its poor physical properties such as mechanical strength and processability, it lacks versatility and has rarely been put to practical use.

[Object of the Invention] The present invention overcomes the above-mentioned problems, and aims to provide a polyolefin resin composition for molding that has excellent strength, rigidity, processability, dimensional stability, etc.

[Structure of the Invention] The polyolefin resin composition of the present invention is a polyolefin resin composition consisting of a plant 5tei mainly composed of fibrous cellulose and a polyolefin resin, based on 100% by weight of the total composition. , the plant fiber has a content of 20 to 6
0% by weight, and the polyolefin resin accounts for the remaining 40 to 801i% by weight, and the polyolefin resin contains a chemically modified polyolefin obtained by adding at least one compound of a carboxylic acid and its anhydride to a polyolefin. The total weight of the compound consisting of at least one of a carboxylic acid and its anhydride added to the chemically modified polyolefin is 0.000% based on 1 weight part of the plant II.
It is characterized by a heavy brass part Ta of 2 to 0.0035.

Here, the term "polyolefin resin" refers to a resin containing a large amount of polyolefin moiety and mainly having the properties of a polyolefin resin, and it does not matter whether the polymers are used alone or as a mixture. In other words, the [polyolefin resin] refers to a chemically modified polyolefin (hereinafter referred to as modified polyolefin) alone, or to the modified polyolefin and an unmodified polyolefin resin such as polypropylene (hereinafter referred to as polyolefin resin, to be distinguished from polyolefin resin). It also refers to those blended with thermoplastic rubber such as polyolefin elastomer.

Since plant fibers mainly composed of cellulose are originally hydrophilic, they have poor affinity with non-polar polyolefin resins, and cannot fully exhibit the characteristics of cellulose, which has the properties of rigid fibers. Therefore, in the present invention, the modified polyolefin is included in a polyolefin resin blended into a vegetable fiber mainly composed of cellulose. When the modified polyolefin is "contained" here, the modified polyolefin is included in all (former) and in part (latter).
There are both. The polyolefin-based m-fat composition of the present invention is a composition comprising the plant fiber and the modified polyolefin in the former case, and a composition comprising the plant Il fiber, the modified polyolefin, and a polyolefin resin in the latter case. In the former case, in order to strengthen the bond with the plant fiber, in the latter case, in order to strengthen the adhesion between the plant fiber and the non-polar polyolefin resin, carboxylic acid or its carboxylic acid is added to the polyolefin so that it has a polar group. In the former case, the entire amount of modified polyolefin to which anhydride or the like has been added is mixed into the polyolefin resin, and in the latter case, a portion thereof is mixed into the polyolefin resin.

The latter utilizes the fact that the polar groups of cellulose and the polar groups of the modified polyolefin are strongly bonded, and that the polyolefin resin is compatible with the polyolefin portion of the base of the modified polyolefin. Note that the modified polyolefin also exhibits excellent functions as a matrix.

The modified polyolefin is one in which at least one compound of a carboxylic acid and its anhydride is additionally bonded to a polyolefin, particularly one mainly composed of polypropylene, so as to have a polar group.

The compound to be modified is usually one compound, but two or more of these compounds may be used.

This is because polypropylene is non-polar and has poor affinity with cellulose, etc., so it needs to be modified to improve this affinity.The types of polyolefins to be modified, differences in chemical structure, etc. are as follows. As explained in the section of polyolefin resin, various resins can be used regardless of the purpose.

The type of the carboxylic acid or its anhydride is not particularly limited as long as it is a compound that can be added to a polyolefin such as polypropylene under an appropriate radical reaction initiator. Usually, a compound having an olefinic double bond is used as the carboxylic acid or its anhydride, and it may be a monocarboxylic acid, a polycarboxylic acid, or an anhydride thereof, but a dicarboxylic acid or anhydride thereof is preferable. The dicarboxylic acid or anhydride thereof may be maleic acid, fumaric acid, maleic anhydride, etc., but an alicyclic dicarboxylic acid having a cis-type double bond in the ring or anhydride thereof is more preferable. For example, the alicyclic dicarboxylic acids include cis-4cyclohexene-
1,2-dicarboxylic anhydride (commonly known as tetrahydrophthalic anhydride), cis-4-cyclohexene-1,2-dicarboxylic acid (commonly known as tetrahydrophthalic acid), endo-bicyclo(
2゜2.1>-5-hebutene-2,3-dicarboxylic anhydride (commonly known as non-hohymic acid), endo-bicyclo(2
,2,1)-5-hebutene-2,3-dicarboxylic acid W (commonly known as Himic acid), endo-bicyclo(2,2,1)-
1,2,3,4,7,7-hexachloro-2-hebutene-5,6-dicarboxylic anhydride (commonly known as chlordane anhydride)
, endo-bicyclo(2,2,1)-1,2,3,4,
Examples include 7,7-hexachloro-2-hebutene-5,6-dicarboxylic acid (commonly known as chlordic acid).

The ratio of the carboxylic acid, etc. added to the polyolefin (hereinafter referred to as the modification rate) is the weight of the carboxylic acid, etc. (hereinafter referred to as the ratio of the carboxylic acid, etc.) to 1 part by weight of the vegetable fiber used. (referred to as parts by weight) is 0.
The proportion may be 0.0002 to 0.0035 parts by weight, and there are no particular limitations other than this. Therefore, the modification rate varies depending on the blending amounts of the plant fiber, the modified polyolefin, and the polyolefin resin.

However, in order not to reduce the chemical stability and good heat resistance that are characteristics of polyolefin resins, especially polypropylene, the modification rate must be kept to a minimum.
Therefore, ``the modification rate is usually the modified polyolefin 1
00% by weight, 1% by weight or less, especially 0.05 to 0.00% by weight.
It is a small amount of 7% by weight. For example, when the present polyolefin resin composition consists of (1) 20% by weight of the plant fiber, 73% by weight of polypropylene, and 7% by weight of modified polyolefin, the relative weight part of the carboxylic acid, etc. is 0.0002% by weight. %, the modification rate is 0.06%, (2) 60! l! ffi%+7) In the case where the vegetable fiber is composed of 8% by weight of polypropylene and 32% by weight of modified polyolefin, when the relative weight part of the carboxylic acid, etc. is 0.0035, the modification rate is 0.
It is 66% by weight. and <3) 40% by weight of vegetable fiber;
In the case of 36% by weight of polypropylene and 24% by weight of modified polyolefin, when the relative weight part of the carboxylic acid etc. is 0.0012 parts by weight, the modification rate is 0.
．． It is 2% by weight.

The polyolefin resin means a resin consisting of a polymer mainly composed of olefins and a mixture of the polymers,
The polymer may be a homopolymer, various copolymers of an olefin and other olefins or other monomers, or may have a different chemical structure (linear, branched, stereoregular, etc.). The polyolefin resin usually includes polypropylene having an isotactic structure as a main component, low-density or high-density polyethylene, copolymers with other olefins, mixtures thereof, etc. In particular, the polypropylene homopolymer resin Or, those mainly composed of polypropylene are most suitable. Note that the polyolefin resin also includes a resin containing relatively nonpolar components other than the olefin moiety to the extent that the function as a polyolefin resin is not impaired.

In this composition, the above-mentioned vegetable fiber is blended in an amount of 20 to 60% by weight based on 100% by weight of the total composition. If the amount of the vegetable fiber is less than 20% by weight, the reinforcing properties of the cellulose fiber will have little effect on improving strength, rigidity, heat resistance, etc.
f! If it exceeds ffi%, the strength becomes brittle and the fluidity deteriorates, making it impractical.

In the present composition, the polyolefin resin part, the modified polyolefin, or the polyolefin resin and the modified polyolefin, is the balance of the vegetable fibers, which is 40 to 80% by weight, based on 100% by weight of the total composition.
is blended. The weight of the compound consisting of at least one of a carboxylic acid and its anhydride added to the modified polyolefin is 0.0002 to 0.0035 parts by weight, preferably 0.0002 to 0.0035 parts by weight, based on 1 part by weight of the vegetable fiber. ．．
0004 to 0.0012 parts by weight. If the weight of the carboxylic acid, etc. is less than 0.0002 parts by weight, the number of bonds between the vegetable fiber and the modified polyolefin decreases, and the reinforcing properties inherent to the vegetable fiber cannot be fully exhibited. If the weight of the carboxylic acid is more than 0.0035 parts by weight, the number of bonds will reach saturation and the modified polyolefin itself will be disadvantageous in terms of strength, heat resistance, etc. compared to the base polyolefin. Further, the blending ratio of the modified polyolefin to the vegetable fiber is, for example, the above modification rate 0.2
In terms of weight %, it can usually be set to a large value of about 10 to 175ffi1%.

In the present composition, a rubber consisting of at least one of a polyolefin elastomer and a thermoplastic rubber such as ethylene-propylene rubber can also be blended. Usually one of these rubbers is used, but a mixture of two or more may be used. Although the thermoplastic rubber can be blended with a polyolefin resin made of the modified polyolefin alone, it is usually blended with a polyolefin resin made of the modified polyolefin and the polyolefin resin. The amount of the thermoplastic rubber added is 3 to 50% by weight, and the other 50 to 97% by weight, based on the remaining 100% by weight after excluding the vegetable fibers and the modified polyolefin. Amount % is polyolefin resin.

In order to uniformly mix the various compounds mentioned above, Mlf and methods generally used to composite resin and filler, such as high-speed rotary mixers, extruders, etc., and combinations thereof, can be applied as they are. However, in order to fully utilize the characteristics of cellulose fibers, it is desirable to use a method that allows good fiber dispersion and does not cause fiber breakage or carbonization. Other additives include various stabilizers, flame retardants, internal mold release agents,
It is also possible to add an inorganic filler or the like.

[Effects of the Invention] The polyolefin resin composition of the present invention is composed of fibrous plant fibers and a modified polyolefin to which carboxylic acid or the like is added, or the polyolefin resin composition is composed of the vegetable fibers, the modified polyolefin, and the polyolefin resin. It is characterized by Therefore, in the former case, the modified polyolefin not only functions as a matrix with excellent strength, but also firmly bonds to the polar groups of the vegetable fibers through the modified portion.

In the latter case, the modified polyolefin is strongly bonded to the vegetable fiber for the same reason, and is extremely well compatible with the polyolefin resin via the polyolefin portion.

This effect is particularly great in the case of a modified polyolefin modified using the same resin as the polyolefin resin. Therefore, the present polyolefin resin composition has significantly improved adhesion between cellulose and the polyolefin system*m as a whole compared to conventional cases, can fully exhibit the rigid properties of cellulose, and has excellent mechanical properties, especially strength. A molding resin composition is provided. In particular, in the case of the former, the olefin portion of the modified polyolefin and the polyolefin resin do not need to be utilized for their compatibility; they are connected by original chemical bonds, so the effect is large, and moreover, there is no need to take the trouble of blending the polyolefin resin. It can be omitted. In the latter case, various polyolefin resins can be used depending on the purpose, so the range of application is wide.

In the polyolefin resin composition of the present invention, the weight of the carboxylic acid, etc. added to the modified polyolefin, which is one component thereof, is 0.0002 to 1 weight part per part by weight of the plant fiber.
It is characterized by a small amount of 0.0035 parts by weight. In addition, the carboxylic acid etc. added to the modified polyolefin, which is one component of the polyolefin resin composition of the present invention, are
The amount can be generally as small as 1% by weight or less based on 100% by weight of the modified polyolefin. Furthermore, since the plant fibers are fibrous, the fibrous cellulose has a very large number of functional groups.

Therefore, in this modified polyolefin, the addition amount and modification rate of the carboxylic acid, etc. to the plant fibers can be made small, and even if they are small, it is possible to Compared to using fillers,
It has extremely good affinity with cellulose fibers, and they bond firmly together. Therefore, the polyolefin resin composition can provide molded articles with excellent mechanical properties and low mold shrinkage.

In the present polyolefin resin composition, rigid cellulose molecules are used as a structural unit in the form of a fibrous aggregate to some extent.

Therefore, this polyolefin resin composition also has flexibility and has extremely good adhesion to the base polymer, so that the physical properties depending on the molding direction, which is a problem when combining glass fiber and the adhesive polymer, can be improved. The difference is extremely small.

As described above, in the polyolefin resin composition of the present invention, the modified polyolefin not only improves adhesiveness but also has a large function as a matrix. In particular, unlike conventional copolymer polymers, the modified polyolefin can be modified while maintaining most of its excellent mechanical and thermal properties if a polyolefin resin such as isotactic polypropylene is used. The function as a matrix can be extremely excellent.

Therefore, the polyolefin resin composition can provide molded products with excellent properties at low cost and without deterioration of properties.

In the polyolefin resin composition of the present invention, thermoplastic rubber such as polyolefin elastomer is added in an amount of 3% by weight based on 100% by weight of the total composition of the polyolefin resin and the rubber.
It can be blended in an amount of up to 50% by weight. Therefore, the present polyolefin resin composition provides a molding resin that has improved flexibility while maintaining strength and the like to some extent.

Since this polyolefin resin composition uses defibrated plant fibers, it is possible to provide a high quality polyolefin resin composition even if waste materials such as waste paper and paper scraps are reused, which helps conserve resources. It is also extremely advantageous in terms of cost.

As described above, the polyolefin resin composition of the present invention provides a relatively strong and inexpensive resin composition for injection molding by reusing waste paper, waste paper, etc., and is suitable for use as industrial materials. It is particularly useful for injection molding of large, thin-walled products, such as air conditioning unit cases for automobile parts.

[Test Examples/Examples] The present invention will be explained below with reference to Examples.

Test Example 1 Polypropylene block copolymer with a melt index of 20 (trade name, BJ320 manufactured by Tonen Petrochemical Co., Ltd.),
Melt index 15, olefin moiety 99.8% by weight, endo-bicyclo[2゜2.1-5-hebutene-
Modified polyolefin to which 0.2% by weight of 2,3-dicarboxylic anhydride has been added (manufactured by Tonen Petrochemical Co., Ltd., C-800X,
Modification rate: 0.2% by weight) was impregnated into 30% and 40% by weight of vegetable fibers, which had been sufficiently defibrated from newspaper and made into fibers, in a high-speed rotating mixer at the blending ratio shown in Table 1.
The compositions (Experiment Nos. 2, 5, 7 to 10) were injection molded to prepare test pieces for each physical property, and the physical properties were measured. The results are shown in Table 1. On the other hand, for comparison, a material (experiment number 1.6) to which no modified polyolefin was added was also prepared, and its physical properties are also shown in Table 1.

Table 1 shows that the physical properties (tensile strength, tensile strength, elongation, flexural modulus, isot impact strength)
It can be seen that the physical properties are improved and the physical properties are saturated when a certain amount of modified polyolefin is added. This result also shows that a high-quality polyolefin resin composition can be provided by reusing newspaper.

The measurement method for each physical property was as follows. That is, the tensile strength is A
STM D-638, flexural modulus was determined in accordance with ASTM D-790, and Izot impact strength was determined in accordance with ASTM D-256. The elongation was determined in accordance with ASTM D-638, and was calculated by dividing the amount of crosshead movement of the tensile testing device by the length of the parallel portion of the test piece.

Example 1 28% by weight of polypropylene, 14% by weight of modified polyolefin, and 28% by weight of an olefin elastomer (Milastomer M4800 manufactured by Mitsui Petrochemicals, Ltd.) shown in Test Example 1 were prepared in advance from newspaper.
The material was impregnated with 30% by weight of the converted plant fiber and its physical properties were measured in the same manner as in Test Example 1 (Experiment No. 411), and the results are shown in Table 2.

Also, instead of the above-mentioned olefin elastomer, ethylene-propylene rubber (JSREP0 manufactured by Japan Synthetic Rubber Co., Ltd.) may be used.
2P) using the compounding ratio shown in Table 2 (Experiment No. 1)
The physical properties of 2) were also measured in the same manner as in Test Example 1, and the results are shown in Table 2.

Both have significantly improved flexibility compared to Test Example 1.

Example 2 56% by weight of polypropylene and 14% by weight of modified polyolefin shown in Test Example 1 were prepared in advance on Xerox paper (
Plant fiber 30 made from Fuji Xerox Co., Ltd.
% by weight in the same manner as in Test Example 1, and the physical properties were measured in the same manner as in Test Example 1. Experiment No. 13)
Shown in the table.

This result is based on Xerox paper (manufactured by Fuji Xerox Co., Ltd.)
This shows that it is possible to provide a high-quality polyolefin resin composition even if it is reused.

Test Example 2 The same materials as those shown in Test Example 1: 60% by weight of polypropylene, 20% by weight of modified polyolefin, and 20% by weight of chopped strand glass fiber with a length of 3 rims.
Using a material composited in a high-speed rotating mixer (comparative material, experiment number 14) and the material of experiment number 3 of Test Example 1,
A flat plate of 100 x 1.00 x 3 mm was obtained by injection molding, and the molding shrinkage in the machine direction and counter-machine direction as well as the tensile strength of a tensile test piece cut out from the plate were measured, and the results are shown in Table 3. From Table 3, the subject material (experiment number 3
) shows that the anisotropy due to molding is extremely small.

Test Example 3 The material of Experiment No. 3 of Test Example 1 and the material of polypropylene homopolymer (Noblen B W +-152 manufactured by Sumitomo Chemical Co., Ltd.) filled with 20% by weight of talc as a comparison (
Experiment No. 15) was used to obtain a bending test piece by injection molding, and the bending strength and bending elastic modulus at room temperature and high temperature atmosphere were measured in accordance with the ASTM D-790 test method, and the results are shown in Table 4. Ta.

It can be seen that this material (Experiment No. 3) has superior physical properties compared to general talc-filled polypropylene materials, especially in the high temperature range.

Test Example 4 Polypropylene homopolymer with melt index 8 (
A polypropylene homopolymer (trade name, Noblen W501 manufactured by Sumitomo Chemical Co., Ltd.) or a polypropylene homopolymer with a melt index of 23 (trade name, Noblen Z101A manufactured by Sumitomo Chemical Co., Ltd.), the modified polyolefin described in Test Example 1, and newspaper were thoroughly opened and made into fibers. A composition (experiment number 16.17) was obtained using the same method as in Test Example 1 using the plant fibers in the proportions shown in Table 5, and the same physical properties were evaluated. Furthermore, a composition (experiment number 18.19) in which no modified polyolefin was added, which did not satisfy the constituent requirements of the present invention, was similarly obtained and evaluated in the same manner, and the results are shown in Table 5.

Similar to the polypropylene block copolymer, the physical properties of polypropylene homopolymer are greatly improved by adding a modified polyolefin, indicating that the present invention is effective regardless of the type of polyolefin.

Claims (4)

[Claims] (1) A polyolefin resin composition consisting of a plant fiber mainly composed of fibrous cellulose and a polyolefin resin, in which the plant fiber contains 20 to 6% by weight of the total composition.
0% by weight, the polyolefin resin accounts for the remaining 40 to 80% by weight, and the polyolefin resin is
It contains a chemically modified polyolefin in which at least one compound of a carboxylic acid and its anhydride is added to a polyolefin. 0.0002 per part by weight of fiber
A polyolefin resin composition characterized in that the amount is 0.0035 parts by weight. (2) The compound consisting of at least one of a carboxylic acid and its anhydride added to the chemically modified polyolefin is an alicyclic dicarboxylic acid having a cis-type double bond in the ring or its anhydride. The polyolefin resin composition according to scope 1. (3) The content of the alicyclic dicarboxylic acid or its anhydride having a cis-type double bond in the ring in the chemically modified polyolefin is 1% by weight or less based on 100% by weight of the chemically modified polyolefin. The polyolefin resin composition according to scope 2. (4) Polyolefin resin is 50% by weight based on the remaining 100% by weight excluding vegetable fibers and chemically modified polyolefins.
97% by weight, and the rubber made of at least one of a polyolefin elastomer and a thermoplastic rubber such as ethylene-propylene rubber is 3 to 50% by weight of the polyolefin resin according to claim 1. Composition.