JP2022097582A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which can obtain a resin molding that achieves both high tensile elastic modulus and improvement of elongation.

SOLUTION: A resin composition contains a masterbatch and a thermoplastic resin, in which the masterbatch contains a compound derived from urea or its derivative, cellulose fibers modified with acid-modified polypropylene, and the acid-modified polypropylene, and satisfies the following conditions (A) and (B), a content of the thermoplastic resin is 220-984 wt.% with respect to 100 wt.% of the amount of the total cellulose fibers of cellulose and hemicellulose in the cellulose fibers contained in the masterbatch. (A) Weight reduction at a temperature rise from 105°C to 300°C with respect to an absolute dry weight of the masterbatch when the temperature is raised under nitrogen atmosphere at 10°C per minute is 10-40%, and weight reduction at a temperature rise from 390°C to 880°C is 5-45%. (B) When a maximum peak intensity in a closed section at both ends of 1315 cm^-1 and 1316 cm^-1 is represented by a, and a maximum peak intensity in an opened section at both ends of 750 cm^-1 and 800 cm^-1 is represented by b, the following expression: b/a>0.1 is satisfied.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a resin composition comprising a masterbatch containing micronized cellulose fibers.

The fine fibrous cellulose obtained by finely breaking the plant fiber includes microfibril cellulose and cellulose nanofiber, and is a fine fiber having a fiber diameter of about 1 nm to several tens of μm. Fine fibrous cellulose is lightweight, has high strength and high elastic modulus, and has a low coefficient of linear thermal expansion, so that it is suitably used as a reinforcing material for resin compositions.

Fine fibrous cellulose is usually obtained in a state of being dispersed in water, and it is difficult to evenly mix it with a resin or the like. Therefore, attempts have been made to chemically modify the cellulose raw material in order to improve the affinity and miscibility with the resin.

For example, in Patent Document 1, a cellulose raw material in which a part of the hydroxy group of cellulose is replaced with a carbamate group is obtained by heat-treating the cellulose raw material and urea, and the cellulose raw material is refined by mechanical treatment to form fine fibers. Obtaining cellulose. The fine fibrous cellulose obtained by this method has lower hydrophilicity than the conventional fine fibrous cellulose and has a high affinity with a resin having low polarity, so that it is highly uniformly dispersed in the resin and has high strength. Gives a complex with. Further, Patent Document 1 discloses that a mixture of the heat-treated cellulose raw material and urea is washed with water or the like to remove unreacted residual urea or the like.

However, the resin complex obtained in Patent Document 1 has not been sufficiently effective in improving the elongation. In general, there is a trade-off between reinforcement (improvement of elastic modulus) and improvement of elongation, so a masterbatch and a resin composition capable of obtaining a resin molded body having both high tensile elastic modulus and improvement of elongation are required. Was being done.

Japanese Unexamined Patent Publication No. 2019-1876

An object of the present invention is to provide a resin composition capable of obtaining a resin molded body having both a high tensile elastic modulus and an improvement in elongation.

The present invention provides:
(1) A resin composition containing a masterbatch and a thermoplastic resin.
The master batch contains a compound derived from urea or a derivative thereof, a cellulose fiber modified with acid-modified polypropylene, and the acid-modified polypropylene, and satisfies the following conditions (A) and (B).
The content of the thermoplastic resin is 220 to 984% by weight based on 100% by weight of the total amount of cellulose fibers including cellulose and hemicellulose in the masterbatch.
(A) With respect to the absolute dry weight of the masterbatch when the temperature is raised at 10 ° C. per minute under a nitrogen atmosphere.
The weight loss when the temperature rises from 105 ° C to 300 ° C is 10 to 40%.
The weight loss when the temperature rises from 390 ° C to 880 ° C is 5 to 45%.
(B) In the infrared absorption spectrum of the masterbatch, the maximum peak intensity in the closed section with 1315 cm ^-1 and 1316 cm ^-1 at both ends is a, and the maximum peak intensity in the open section with 750 cm ^-1 and 800 cm ^-1 at both ends. When b, the following equation is satisfied.
b / a> 0.1
(2) Further, the resin composition according to (1), wherein the masterbatch satisfies the following condition (C).
(C) A dumbbell type test piece obtained by adding 8 parts of polypropylene to 1 part of the total amount of cellulose fibers containing cellulose and hemicellulose among the cellulose fibers contained in the master batch, kneading at 180 ° C., and then molding. The common logarithmic value of the relative tensile modulus when the tensile modulus of polypropylene alone is set to 1 is X, and the tensile strain value of the resin molded product consisting of cellulose fiber and polypropylene only. The following equation is satisfied when the value of the relative tensile strain when is 1 is Y.
Y> -14.9X + 4.7

According to the present invention, it is possible to provide a resin composition capable of obtaining a resin molded body having both a high tensile elastic modulus and an improvement in elongation.

Hereinafter, the masterbatch contained in the resin composition of the present invention will be described. In the present invention, "-" includes a fractional value. That is, "X to Y" includes the values X and Y at both ends thereof.

The master batch of the present invention contains a compound derived from urea or a derivative thereof, a cellulose fiber modified with acid-modified polypropylene, and the acid-modified polypropylene, and satisfies the following conditions (A) and (B).
(A) When the temperature is raised at 10 ° C. per minute under a nitrogen atmosphere, the weight reduction when the temperature is raised from 105 ° C. to 300 ° C. is 10 to 40% with respect to the absolute dry weight of the masterbatch. The weight loss when the temperature rises from 390 ° C to 880 ° C is 5 to 45%.
(B) In the infrared absorption spectrum of the masterbatch, the maximum peak intensity in the closed section with 1315 cm ^-1 and 1316 cm ^-1 at both ends is a, and the maximum peak intensity in the open section with 750 cm ^-1 and 800 cm ^-1 at both ends. When b, the following equation is satisfied.
b / a> 0.1

(Cellulose fiber)
The cellulose fiber used in the present invention has a weighted average fiber length (length average fiber length) in the range of 0.2 to 1.5 mm, preferably 0.3 to 1.0 mm. Such cellulose fibers can be obtained, for example, by pulverizing or beating the cellulose raw material.

(Cellulose raw material)
In the present invention, the cellulose raw material may be any material in the form mainly composed of cellulose, and contains lignocellulose (NUKP), and pulp (bleached or unbleached wood pulp, bleached or unbleached non-wood). Natural cellulose such as cellulose produced by microorganisms such as pulp, purified linter, jute, Manila hemp, Kenaf, etc.), cellulose produced by microorganisms such as acetic acid bacteria, after dissolving cellulose in some solvent such as copper ammonia solution, morpholin derivative, etc. Re-precipitated regenerated cellulose, fine cellulose obtained by depolymerizing cellulose by subjecting the above-mentioned cellulose raw material to hydrolysis, alkaline hydrolysis, enzymatic decomposition, blasting treatment, mechanical treatment such as vibration ball mill, etc., various cellulose derivatives, etc. Illustrated.

Lignocellulosic is a complex carbohydrate polymer that constitutes the cell wall of a plant, and is mainly composed of polysaccharides cellulose and hemicellulose, and lignin which is an aromatic polymer. The content of lignin can be adjusted by delignin or bleaching the pulp or the like as a raw material.

In the present invention, when pulp is used as a raw material for cellulose, either unbeaten or beaten pulp may be used, but it is preferable to use pulp that has been beaten. As a result, it can be expected that the specific surface area of the pulp will increase and the urea reaction amount will increase. The degree of beating treatment is preferably 400 mL or less with a drainage degree (C.S.F), more preferably about 100 mL to 200 mL. If the drainage degree exceeds 400 mL, the effect cannot be exhibited, and if it is less than 100 mL, the effect of improving the strength is hindered when the reinforced resin is used because the fibers are shortened due to damage to the cellulose fibers. Further, by performing this beating treatment, the range of the weighted average fiber length (length average fiber length) is 0.2 to 1.5 mm, preferably 0.3 to 1 when the washing treatment and the drying treatment described later are performed. If it falls within the range of 0.0 mm, the crushing step described later may be omitted.

Examples of the beating method include mechanically (mechanically) treating pulp fibers using a known beating machine. As the beating machine, a beating machine usually used for beating pulp fibers can be used, for example, a Niagara beater, a PFI mill, a disc refiner, a conical refiner, a ball mill, a stone mill type mill, a sand grinder mill, and an impact. Mills, high-pressure homogenizers, low-pressure homogenizers, dyno mills, ultrasonic mills, kanda grinders, attritors, vibration mills, cutter mills, jet mills, breakers, household juicer mixers, and mortars. Among them, Niagara beater, disc refiner and conical refiner are preferable, and disc refiner and conical refiner are more preferable.

In the beating process, dehydration may be performed if necessary. As the dehydration method, a pressure dehydration method using a screw press, a vacuum dehydration method by volatilization, etc. can be carried out, but the centrifugal dehydration method is preferable from the viewpoint of efficiency. Dehydration is preferably carried out until the solid content in the solvent reaches about 10 to 60%.

The cellulose fiber used in the present invention is subjected to a drying treatment after the dehydration step and before being used in a pulverization step carried out as necessary. The drying process can be performed using, for example, a microwave dryer, a blower dryer or a vacuum dryer (vacuum dryer), but a drum dryer, a paddle dryer, a nouter mixer, and batch drying with stirring blades can be performed. A dryer that can dry while stirring is preferable. Drying is preferably performed as much as possible until the water content of the cellulose fibers is 0.1 to 10%, preferably about 1 to 5%.

The cellulose fibers contained in the masterbatch of the present invention are modified with a compound derived from urea or a derivative thereof, and acid-modified polypropylene.

(Acid-modified polypropylene)
The acid-modified polypropylene contained in the master batch of the present invention is a high molecular resin having a low molecular weight dicarboxylic acid capable of forming an acid anhydride such as maleic acid, succinic acid, and glutaric acid on the polyolefin chain of polypropylene. Of these, it is preferable to use maleic anhydride-modified polypropylene (MAPP) to which maleic acid is added. In the present invention, the acid-modified polypropylene has a function as a compatible resin. The compatible resin has a function of uniformly mixing the cellulose fibers having different hydrophobicities and the thermoplastic resin and improving the adhesion.

The cellulose fiber modified by the compound derived from urea or a derivative thereof and the acid-modified polypropylene used in the present invention can be obtained by, for example, adding cellulose fiber, acid-modified polypropylene, and urea at the same time and kneading. .. The mechanism of the phenomenon that the strength of the cellulose fiber in the polyolefin resin is improved by this operation has not been clarified at this time, but it is possible to explain a part of it by considering as follows. That is, urea is decomposed into ammonia and isocyanic acid when the temperature exceeds 135 ° C., but by kneading urea at the same time as the cellulose fiber, the unmodified hydroxyl group newly emerged from the inside of the cellulose fiber and the generated isocyanic acid are generated by the kneading. It is considered that it reacts with acid to promote the formation of urethane bonds, and it is presumed that the hydrophobicity is enhanced as compared with the cellulose fiber not treated with urea. Furthermore, by melt-kneading at the same time as acid-modified polypropylene having acid anhydride, the interaction between the amino group newly introduced by urea treatment on the surface of the cellulose fiber and the carboxylic acid of the acid-modified polypropylene is promoted, and the cellulose becomes stronger. It is considered that it is possible to form a composite of the fiber and the acid-modified polypropylene.

The amount of urea required to achieve the above mechanism is 100% by weight of the amount of cellulose fibers including cellulose and hemicellulose contained in the cellulose fibers (hereinafter, this may be referred to as "cellulose amount"). % Is preferably 10 to 100% by weight, more preferably 20 to 100% by weight, still more preferably 30 to 70% by weight.

Factors that determine the characteristics of the acid-modified polypropylene used in the present invention as a compatible resin are the amount of dicarboxylic acid added and the weight average molecular weight of the polyolefin resin as the base material. A polyolefin resin having a large amount of dicarboxylic acid added enhances compatibility with a hydrophilic polymer such as cellulose, but the molecular weight of the resin becomes small during the addition process, and the strength of the molded product decreases. As an optimum balance, the addition amount of the dicarboxylic acid is 20 to 100 mgKOH / g, more preferably 45 to 65 mgKOH / g. When the addition amount is small, the number of points that interact with the urea-derived amino group in the resin is reduced. Further, when the addition amount is large, the strength as a reinforced resin is not achieved due to self-aggregation due to hydrogen bonds between carboxyl groups in the resin and a decrease in the molecular weight of the olefin resin as a base material due to an excessive addition reaction. The molecular weight of the polyolefin resin is preferably 35,000 to 250,000, more preferably 50,000 to 100,000. When the molecular weight is small from this range, the strength of the resin is lowered, and when the molecular weight is large from this range, the viscosity at the time of melting is greatly increased, the workability at the time of kneading is lowered, and molding defects are caused.

The amount of the acid-modified polypropylene having the above characteristics is preferably 10 to 70% by weight, more preferably 20 to 50% by weight, based on the amount of cellulose. If the addition amount exceeds 70% by weight, it is considered that inhibition of introduction of urea-derived isocyanic acid into the cellulose fiber and formation of a complex of acid-modified polypropylene and urea are promoted, and the effect of the present invention is not exhibited.

Further, the acid-modified polypropylene may be used alone or as a mixed resin of two or more kinds.

In the masterbatch of the present invention, when the temperature is raised at 10 ° C. per minute under a nitrogen atmosphere, the weight reduction when the temperature is raised from 105 ° C. to 300 ° C. is 10 to 40% with respect to the absolute dry weight of the masterbatch. It is preferably 12 to 32%, and the weight loss at the time of temperature rise from 390 ° C to 880 ° C is 5 to 45%, preferably 10 to 35%. Here, the weight loss when the temperature is raised from 105 ° C. to 300 ° C. is due to the decomposition of urea and its derivative, and the weight loss when the temperature is raised from 390 ° C. to 880 ° C. is due to the decomposition of the acid-modified polypropylene. It is derived from decomposition.

The above thermogravimetric reduction rate can be measured using, for example, a TG / DTA device (manufactured by Hitachi High-Tech Science Corporation).

In the master batch of the present invention, the maximum peak intensity in the closed section having 1315 cm ^-1 and 1316 cm ^-1 at both ends in the infrared absorption spectrum is a, and the maximum peak intensity in the open section having 750 cm ^-1 and 800 cm ^-1 at both ends. The maximum peak intensity ratio b / a when b is greater than 0.05, more preferably greater than 0.1, from the viewpoint of the degree of compounding of the cellulose fiber and the urea-derived compound. The maximum peak intensity a in the closed section having 1315 cm ^-1 and 1316 cm ^-1 at both ends is a peak derived from the cellulose skeleton. The maximum peak intensity b in the open section having 750 cm ^-1 and 800 cm ^-1 at both ends is a peak derived from the angular vibration of the triazine ring and a peak derived from the addition of urea.

The master batch of the present invention was obtained by adding 8 parts of polypropylene to 1 part of the amount of cellulose fibers in which cellulose and hemicellulose were combined among the cellulose fibers contained in this master batch, kneading at 180 ° C., and then molding. When a tensile test is performed on a dumbbell type test piece, the common logarithmic value of the relative tensile modulus when the tensile modulus of polypropylene alone is set to 1 is X, and a resin molded body consisting of cellulose fibers and polypropylene only. The following equation is satisfied when the relative tensile strain value is Y when the tensile strain value is 1.
Y> -14.9X + 4.7

When the above formula is satisfied, it means that a high elastic modulus, which is generally a trade-off, and an improvement in elongation can be achieved at the same time.

The method for producing the master batch of the present invention is not particularly limited, and can be obtained, for example, by simultaneously putting cellulose fibers, acid-modified polypropylene, and urea into a kneader and kneading them.

(Kneading pretreatment-crushing)
A step of crushing the cellulose fibers may be provided before the kneading. By using the crushed cellulose fibers, when the cellulose fibers are put into the kneader, the fiber lumps of the cellulose fibers are in a state of being appropriately unraveled, and the bridge (clogging) at the charging port (chute part) and the pulp biting into the screw are poor. Can be suppressed.

The crushed cellulose fiber is preferably used by passing it through a screen, and it is preferable to use a screen having a diameter of 1 mm or more and 5 mm or less, preferably a diameter of 3 mm or more and 5 mm or less. The weighted average fiber length (length average fiber length) of the cellulose fibers thus obtained is preferably about 0.20 to 1.5 mm, more preferably 0.30 to 1.0 mm.

As the cellulose fiber to be pulverized, it is preferable to use a dried cellulose fiber from the viewpoint of reducing the drying load at the time of kneading.

(Kneading)
In the above kneading, cellulose fibers having a weighted average fiber length of 0.20 to 1.50 mm, preferably 0.30 to 1.00 mm, acid-modified polypropylene, and urea are simultaneously put into a kneader and melt-kneaded. The weighted average fiber length (length average fiber length) of the cellulose fiber can be measured using a fiber tester (manufactured by L & W) or the like. When putting into the kneader, various commercially available feeders and side feeders can be used. When the compatible resin and urea are powdered in advance, cellulose fibers, acid-modified polypropylene, and urea can be mixed and charged by a commercially available mixer or the like before charging. Even when the acid-modified polypropylene or the like is not powdered, it can be charged by preparing a plurality of feeders, for example, a feeder for pellets and a feeder for cellulose fibers. In the first kneading step, the blending amount of the cellulose fiber content of the cellulose fiber charged into the kneader is preferably 35 to 85% by weight with respect to the total amount of the cellulose fiber content, the acid-modified polypropylene and urea. It is more preferably 40 to 65% by weight.

(Kneader)
As the kneading machine used in the above kneading, an acid-modified polypropylene and urea can be melt-kneaded, and a kneading machine having a strong kneading force for promoting nanonization of cellulose fibers is preferable. It is desirable to use a multi-screw kneader such as, etc., and to include a plurality of kneading, rotors, etc. in the parts constituting the screw. As long as the kneading power equivalent to the above can be secured, for example, a kneading machine such as a bench roll, a Banbury mixer, a kneader, or a planetary mixer may be used. Further, in order to remove water and volatile urea attached to the cellulose fibers, it is preferable to knead a part or all of the inside of the kneader barrel under reduced pressure.

The set temperature for melt-kneading can be adjusted according to the melt temperature of the acid-modified polypropylene used. When maleic anhydride-modified polypropylene suitable for the present invention is used as the acid-modified polypropylene, the temperature is preferably 135 ° C. or higher in order to promote the decomposition of urea, and a compatibilized resin having a dicarboxylic acid residue capable of forming an acid anhydride. It is more preferable that the temperature is 160 ° C. or higher, which is melted and partially closed by dehydration. Isocyanic acid is generated from urea by the above temperature setting, and forms a urethane bond with an unmodified hydroxyl group on the cellulose fiber. Thereby, the introduction of an amino group on the cellulose fiber is achieved, and it becomes possible to promote the interaction with the acid-modified polypropylene. Further, at the above temperature, the dicarboxylic acid residue in the acid-modified polypropylene is closed to form an acid anhydride, so that an esterification reaction with the cellulose fiber occurs, and a stronger resin composite can be formed. On the other hand, when the kneading temperature exceeds 200 ° C., the polypropylene resin as the base material begins to deteriorate and the strength decreases.

Cellulose fibers, acid-modified polypropylene and urea charged into the kneader during the above kneading are melt-kneaded, and at least a part of the cellulose fibers are defibrated by the shearing force generated during the melt-kneading, and the master containing the cellulose nanofibers. The batch is prepared.
The cellulose nanofibers are preferably fine fibers having a fiber diameter of about 1 to 1000 nm and an aspect ratio of 100 or more. In the masterbatch of the present invention, the cellulose nanofibers may occupy a majority, and unfibered fibers may be contained in the masterbatch.

(Washing)
The masterbatch of the present invention may be washed with water after the above kneading. By washing the above-mentioned kneaded product with water, residual urea in the masterbatch and urea-derived by-products (biuret, cyanuric acid, melamine, etc.) that can be slightly produced by the above-mentioned kneading can be substantially removed, and residual urea can be removed. It is considered that the aggregation of fibers and the like caused by urea and its by-products is eliminated. Therefore, the resin molded body obtained by using the masterbatch after cleaning is excellent in tensile strength and elongation.

The master batch obtained by the above kneading may be washed with water by any method as long as it can be stirred or dispersed. For example, stirring with a three-one motor, an agitator, a homomixer, a homogenizer, a mixer, or the like can be used. Examples include known stirrers or dispersers.

The temperature of the water used for washing is room temperature to 100 ° C., 50 to 100 ° C., preferably 60 to 90 ° C., and more preferably 60 to 80 ° C. from the viewpoint of improving the solubility of residual urea and its by-products. The total cleaning time is preferably 10 minutes to 24 hours, more preferably 0.5 hours to 5 hours, and even more preferably 1 hour to 3 hours in consideration of efficiency. From the viewpoint of chemical equilibrium, hot water is exchanged 0 to 10 times, preferably 1 to 5 times within the washing time. The weight% of the kneaded product obtained in the first kneading step at the time of washing is preferably 0.1 to 50% by weight, more preferably 0.1 to 15% by weight, from the viewpoint of chemical equilibrium. Further, it is preferable to wash until the amount of residual urea is less than 1%, particularly less than 0.1%. Since the thermal decomposition start temperature of urea is 135 ° C., the amount of residual urea can be determined from the weight loss when heated at 140 ° C. for 270 minutes, for example.

During the production of the masterbatch of the present invention, the ring closure and ring opening prevention of the modifying group in the compatibilizer in the diluting step, the decomposition prevention of the cellulose fiber and the thermoplastic resin used as the diluting resin by the remaining water, and the kneading From the viewpoint of reducing the drying load, it is preferable to dry and use the kneaded product washed above. The drying process can be performed using, for example, a microwave dryer, a blower dryer or a vacuum dryer, but a drum dryer, a paddle dryer, a nouter mixer, a batch dryer with a stirring blade, or the like is used for stirring. A dryer that can dry while still is preferable. Drying is preferably performed until the water content of the kneaded product reaches about 0.1 to 5%.

(Resin composition)
A resin composition can be obtained by adding a thermoplastic resin to the masterbatch of the present invention and, for example, melt-kneading (diluting kneading).

(Thermoplastic resin)
As the thermoplastic resin used in the present invention, the following general thermoplastic resins having a melting temperature of 250 ° C. or lower can be used.

That is, polyolefin resin, polyamide resin, polyvinyl chloride, polystyrene, polyvinylidene chloride, fluororesin, (meth) acrylic resin, polyester, polylactic acid, copolymer resin of lactic acid and ester, polyglycolic acid, acrylonitrile-butadiene- A styrene copolymer (ABS resin), polyphenylene oxide, polyurethane, polyacetal, vinyl ether resin, polysulfone resin, cellulose resin (triacetylated cellulose, diacetylated cellulose, etc.) and the like can be used.

As the polyolefin resin, polyethylene, polypropylene (hereinafter, also referred to as “PP”), ethylene-propylene copolymer, polyisobutylene, polyisoprene, polybutadiene, etc. can be used, and the viewpoint of interaction with the compatible resin can be used. Therefore, when MAPP is used, it is preferable to use polypropylene.

The content of the thermoplastic resin in the resin composition of the present invention is the cellulose fiber content of the combined cellulose and hemicellulose among the cellulose fibers contained in the master batch from the viewpoint that a reinforcing effect can be obtained while maintaining a low density. 220 to 984% by weight is preferable, 330 to 940% by weight is preferable, and 452 to 925% by weight is more preferable with respect to 100% by weight of the amount.

(Dilution kneading)
The method of adding the thermoplastic resin to the masterbatch of the present invention and diluting and kneading is not particularly limited. For example, even if both components are mixed at room temperature without heating and then melt-kneaded, they are mixed while heating. It may be melt-kneaded.

As the kneading machine when the thermoplastic resin is added and melt-kneaded, the same kneading machine as that used in the above-mentioned kneading can be used. Further, the melt-kneading temperature can be adjusted according to the acid-modified polypropylene (compatible resin) used in the above-mentioned kneading. The set heating temperature at the time of melt-kneading is preferably about ± 20 ° C., which is the minimum processing temperature recommended by the thermoplastic resin supplier. When polypropylene is used as the thermoplastic resin, the melt-kneading temperature is preferably 140 to 230 ° C, more preferably 160 to 200 ° C. By setting the mixing temperature in this temperature range, the cellulose fiber and the resin can be uniformly mixed.

The resin composition produced by the production method of the present invention further comprises, for example, a surfactant; a polysaccharide such as starch and an alginic acid; a natural protein such as gelatin, gelatin and casein; tannin, zeolite, ceramics, metal powder and the like. Inorganic compounds; colorants; plastics; fragrances; pigments; flow regulators; leveling agents; conductive agents; antistatic agents; ultraviolet absorbers; ultraviolet dispersants; deodorants, antioxidants, etc. May be. As the content ratio of any additive, it may be appropriately contained as long as the effect of the present invention is not impaired.

According to the present invention, it is possible to provide a masterbatch and a resin composition capable of obtaining a resin molded body having both a high tensile elastic modulus and an improvement in elongation.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Measurement of thermogravimetric reduction rate)
The thermogravimetric reduction rate was measured for 10 mg of the master batches obtained in Examples and Comparative Examples. The temperature condition was maintained at 105 ° C. for 10 minutes, and then the temperature was raised to 900 ° C. at a rate of 10 ° C. per minute. The measurement was performed in a nitrogen atmosphere. Table 1 shows the weight decrease when the temperature rises from 105 ° C. to 300 ° C. and the weight decrease when the temperature rises from 390 ° C. to 880 ° C. The weight loss when the temperature rises from 105 ° C to 300 ° C is due to urea or a compound derived from urea, and the weight loss when the temperature is raised from 390 ° C to 880 ° C is derived from the amount of acid-modified polypropylene used as the compatibilizing resin. ..

(Measurement of infrared absorption spectrum)
Infrared absorption spectra (IR spectra) were measured in an absolutely dry state for the master batches obtained in Examples and Comparative Examples. Maximum peak intensity ratio when the maximum peak intensity in the closed section with 1315 cm ^-1 and 1316 cm ^-1 at both ends in the IR spectrum is a, and the maximum peak intensity in the open section with 750 cm ^-1 and 800 cm ^-1 at both ends is b. b / a is shown in Table 1. The maximum peak intensity a is a peak derived from the cellulose skeleton. The maximum peak intensity b is a peak derived from the angular vibration of the triazine ring and a peak derived from the addition of urea. When b / a> 0.05 is satisfied, this masterbatch is obtained by kneading with urea, and indicates that the resin complex is a composite of cellulose fibers and a compound derived from urea.

(Measurement of tensile elastic modulus and tensile strain)
The resin compositions obtained in Examples and Comparative Examples were put into a pelletizer to obtain a pellet-shaped resin molded product. 150 g of pellet-shaped resin molded body is put into a small molding machine (“MC15” manufactured by Xplore Instruments), and the temperature of the heating cylinder (cylinder) is 200 ° C. and the mold temperature is 40 ° C., and the dumbbell type test piece (type). A12, JIS K 7139) was molded. The obtained test piece was used with a precision universal testing machine (“Autograph AG-Xplus” manufactured by Shimadzu Corporation) at a test speed of 1 mm / min, an initial distance between marked lines of 30 mm, tensile modulus and tensile strength. The strain (strain until break, elongation) was measured. Of the measured values, the ratio of the measured values of each sample when the tensile elastic modulus of PP, which is a diluting resin, is 1, is defined as the relative tensile elastic modulus, and the results are shown in Table 1. Further, the ratio of the measured values of each sample when the tensile strain value of the resin molded body composed of cellulose fiber and PP is set to 1 is defined as the relative tensile strain, and the results are shown in Table 1. When the common logarithm of the relative tensile modulus is X and the value of the relative tensile strain is Y, and the following equation is satisfied, it is shown that both high tensile modulus and improvement in elongation are compatible.
Y> -14.9X + 4.7

A resin molded body composed of only cellulose fibers and PP was obtained by the following method. The water-containing softwood unbleached kraft pulp (NUKP) was dried and pulverized with a super mixer (SMV-Ba, manufactured by Kawata Co., Ltd.). The fiber length of the cellulose fiber was measured by a fiber tester (manufactured by L & W), and the weighted average fiber length was 0.98 mm. The obtained cellulose fiber (394.2 g as an absolute dried product, of which the amount of cellulose including lignin-free cellulose and hemicellulose: 360 g) and polypropylene resin (108 g) are placed in a polyethylene bag, shaken and mixed. did. 502.2 g of the obtained mixture was put into a kneader using a feeder (manufactured by Technobel Co., Ltd.) attached to the above-mentioned twin-screw kneader, and kneaded at 180 ° C. to produce a masterbatch. 861 parts of PP as a thermoplastic resin was added to the obtained master batch with respect to 100 parts by weight of the amount of cellulose in the cellulose fibers, and kneaded at 180 ° C. with the twin-screw kneader to obtain a resin composition. ..

(Kneader and operating conditions used to manufacture masterbatch and resin composition)
"MFU15TW-45HG-NH" twin-screw kneader manufactured by Technobel Co., Ltd. Screw diameter: 15 mm, L / D: 45, processing speed: 300 g / hour The screw rotation speed was 200 rpm.

(Material used for manufacturing masterbatch and resin composition)
(A) Cellulose fiber (b) Acid-modified polypropylene (compatible resin)
Maleic anhydride-modified polypropylene (MAPP): (Toyobo Co., Ltd. Toyo Tuck PMA-H1000P: Addition of dicarboxylic acid 57 mgKOH / g)
(C) Urea: (manufactured by Wako Pure Chemical Industries, Ltd.)
(D) Thermoplastic resin-Polypropylene (PP): (PP MA04A manufactured by Japan Polypropylene Corporation)

(Example 1)
(Preparation of Cellulose Fiber 1)
20 kg (solid content 10 kg) of hydrous coniferous unbleached kraft pulp (NUKP) that had been beaten to 150 mL of CSF was put into a stirrer (“FM150L” manufactured by Nippon Coke Industries Co., Ltd.), and then stirring was started. Then, it was dehydrated under reduced pressure at 80 ° C. The water content of the obtained cellulose fiber 1 was measured with an infrared moisture meter. The water content was 1.7% by weight. The weighted average fiber length measured by a fiber tester (manufactured by L & W) was 0.90 mm.

(Manufacturing of masterbatch)
Cellulose fiber 1 subjected to the above beating treatment (438 g as an absolute dry product, of which the amount of cellulose obtained by combining cellulose and hemicellulose: 400 g), a powdery compolytic resin (MAPP: 120 g), and a powdered urea (200 g). : 50% of the amount of cellulose) was placed in a polyethylene bag and mixed by shaking. 758 g of the obtained mixture was put into a kneader using a feeder (manufactured by Technobel Co., Ltd.) attached to the above-mentioned twin-screw kneader, and kneaded at 180 ° C. to produce a masterbatch.

(Washing)
600 g of the masterbatch obtained above was washed with 7.5 L of hot water at 80 ° C. for 2 hours. Hot water was exchanged once during washing. Stirring was performed using a Primix Automixer type 40. The temperature was maintained by a water bath. After washing, the masterbatch was placed in a dryer and dried at 105 ° C. overnight (or until it reached a constant weight).

(Manufacturing of resin composition)
To the masterbatch obtained after washing and drying, 8 parts of PP as a thermoplastic resin was added to 1 part of the amount of cellulose fibers contained in the masterbatch, and the mixture was kneaded at 180 ° C. with the twin-screw kneader. Obtained a resin composition.

(Example 2)
Instead of cellulose fiber 1, NUKP without beating treatment, which was dried and pulverized with a super mixer (manufactured by Kawata Co., Ltd., SMV-Ba), was used, and the amount of urea added was 280 g (70% of the amount of cellulose). A masterbatch was produced in the same manner as in Example 1 except that the blending amount was changed. Further, the resin composition was produced in the same manner as in Example 1 except that the obtained masterbatch was not washed and then dried, and the obtained masterbatch was used as it was. The weighted average fiber length measured by a fiber tester (manufactured by L & W) was 0.98 mm.

(Example 3)
The resin composition was produced in the same manner as in Example 1 except that the masterbatch was produced in the same manner as in Example 1, no washing and subsequent drying were performed, and the obtained masterbatch was used as it was.

(Comparative Example 1)
A masterbatch was produced in the same manner as in Example 1 except that NUKP, which had been subjected to the same dry pulverization treatment as in Example 2 and was not beaten, was used instead of the cellulose fiber 1, and urea was not added. .. Further, the resin composition was produced in the same manner as in Example 1 except that the obtained masterbatch was not washed and then dried, and the obtained masterbatch was used as it was.

As shown in Table 1, a compound derived from urea or a derivative thereof of the present invention, a cellulose fiber modified with acid-modified polypropylene, and the acid-modified polypropylene are contained, and the weight is reduced and specified when the temperature is raised to a specific temperature. By using a master batch in which the absorbance ratio of the region satisfies a specific range, it was possible to obtain an excellent molded product having both high tensile strength and improved elongation.

Claims (2)

A resin composition containing a masterbatch and a thermoplastic resin.
The master batch contains a compound derived from urea or a derivative thereof, a cellulose fiber modified with acid-modified polypropylene, and the acid-modified polypropylene, and satisfies the following conditions (A) and (B).
The content of the thermoplastic resin is 220 to 984% by weight based on 100% by weight of the total amount of cellulose fibers including cellulose and hemicellulose in the masterbatch.
(A) With respect to the absolute dry weight of the masterbatch when the temperature is raised at 10 ° C. per minute under a nitrogen atmosphere.
The weight loss when the temperature rises from 105 ° C to 300 ° C is 10 to 40%.
The weight loss when the temperature rises from 390 ° C to 880 ° C is 5 to 45%.
(B) In the infrared absorption spectrum of the masterbatch, the maximum peak intensity in the closed section with 1315 cm ^-1 and 1316 cm ^-1 at both ends is a, and the maximum peak intensity in the open section with 750 cm ^-1 and 800 cm ^-1 at both ends. When b, the following formula is satisfied.
b / a> 0.1 Further, the resin composition according to claim 1, wherein the masterbatch satisfies the following condition (C).
(C) A dumbbell type test piece obtained by adding 8 parts of polypropylene to 1 part of the total amount of cellulose fibers containing cellulose and hemicellulose among the cellulose fibers contained in the master batch, kneading at 180 ° C., and then molding. The common logarithmic value of the relative tensile modulus when the tensile modulus of polypropylene alone is set to 1 is X, and the tensile strain value of the resin molded product consisting of cellulose fiber and polypropylene only. The following equation is satisfied when the value of the relative tensile strain when is 1 is Y.
Y> -14.9X + 4.7