JP5429933B2 - Manufacturing method of resin molding - Google Patents

Description

  The present invention relates to a method for producing a resin molded article having excellent transparency, flexibility, heat resistance, and dimensional stability.

  Cellulose derivatives such as cellulose acetate are resins made from plant-derived non-petroleum and have a small impact on the global environment, and therefore, their use is demanded as an alternative to resins made from petroleum. Although a cellulose derivative is excellent in mechanical properties and thermal properties, it has a problem that it is difficult to melt-mold alone because the difference between the melting temperature and the thermal decomposition temperature is small.

  In order to solve the above-mentioned problem, in Patent Document 1, a polymer obtained by suspension polymerization of a vinyl monomer in the presence of a cellulose derivative is blended with a thermoplastic resin and melt-molded to obtain a resin molded body containing the cellulose derivative. A method of obtaining has been proposed.

JP 2009-155626 A

However, since the method proposed in Patent Document 1 obtains a resin molded body by melt molding, the thermal history is large, and the melt fluidity of the polymer is low, so that the melt fluidity is high for melt molding. A thermoplastic resin must be further added, and it is difficult to mold the polymer alone, and the resulting resin molded body has insufficient heat resistance.
The objective of this invention is providing the method of manufacturing the resin molding which is excellent in transparency, a softness | flexibility, heat resistance, and dimensional stability.

In the present invention, cellulose diacetate (a) 1 to 80% by mass and (meth) acrylate monomer (b) 20 to 99% by mass (however, cellulose diacetate (a) and (meth) acrylate monomer (b ) Is a method for producing a resin molded product obtained by cast polymerization of a mixture comprising 100% by mass), and the swelling ratio of cellulose diacetate (a) with respect to (meth) acrylate monomer (b) is It is a manufacturing method of the resin molding which is 2.0 or more.

  The resin molded product obtained by the production method of the present invention is excellent in transparency, flexibility, heat resistance, and dimensional stability, and therefore is suitably used in various applications such as automobiles, home appliances, OA equipment parts, agricultural materials, and the like. Can do. Moreover, in the resin material, substitution from the raw material derived from petroleum to the raw material derived from non-petroleum can be promoted.

FIG. 1 is a diagram of the storage elastic modulus of the resin molded bodies obtained in Example 3 and Comparative Example 4. FIG. 2 is a diagram of the storage elastic modulus of the resin moldings obtained in Example 1 and Reference Example 1. FIG. 3 is a diagram of the storage elastic modulus of the resin moldings obtained in Example 2 and Reference Example 2. FIG. 4 is a diagram of the linear expansion coefficient of the resin molded body obtained in Example 1. FIG. 5 is a diagram of the linear expansion coefficient of the resin molded product obtained in Example 2. FIG. 6 is a diagram of the linear expansion coefficient of the resin molded body obtained in Example 3. FIG. 7 is a diagram of the linear expansion coefficient of the resin moldings obtained in Reference Examples 1 and 2. FIG. 8 is a photograph of the resin molded product obtained in Example 1. FIG. 9 is a photograph of the resin molded body obtained in Example 1.

  Hereinafter, the present invention will be described in detail.

  The cellulose derivative (a) of the present invention refers to a cellulose functional group substituted by a chemical reaction. Among these cellulose derivatives, a cellulose ester obtained by esterifying a hydroxyl group of cellulose or the like is preferable from the viewpoint of the swelling ratio of the cellulose derivative (a) with respect to the vinyl monomer (b) and the transparency of the obtained resin molding.

  Examples of the cellulose ester include cellulose acetate such as cellulose diacetate and cellulose triacetate, cellulose acetate propionate, and cellulose acetate butyrate. Among these cellulose esters, cellulose acetates such as cellulose diacetate and cellulose triacetate are preferable, and cellulose diacetate is more preferable.

  The degree of acetylation of cellulose acetate is preferably 40 to 62%, more preferably 50 to 61%, and still more preferably 52 to 59%.

  These cellulose derivatives (a) may be used individually by 1 type, and may use 2 or more types together.

The vinyl monomer (b) of the present invention includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, n-propyl (meth) acrylate, n -(Meth) acrylate monomers such as butyl (meth) acrylate, cyanoethyl (meth) acrylate and cyanobutyl (meth) acrylate; fluorinated (meth) acrylates such as 2,2,2-trifluoroethyl (meth) acrylate An aromatic vinyl monomer such as styrene and α-methylstyrene; a vinyl cyanide monomer such as (meth) acrylonitrile; and a carboxyl group-containing monomer such as (meth) acrylic acid. Among these vinyl monomers (b), methyl (meth) acrylate, ethyl (meth) acrylate, and n-butyl (meth) acrylate are preferable from the viewpoint of the transparency and flexibility of the obtained resin molding. Acrylate, ethyl acrylate and n-butyl acrylate are more preferable, and methyl acrylate is still more preferable.
These vinyl monomers (b) may be used individually by 1 type, and may use 2 or more types together.
In the present invention, (meth) acrylate represents acrylate or methacrylate.

The swelling ratio of the cellulose derivative (a) with respect to the vinyl monomer (b) of the present invention is a value determined by the measurements shown in the following (A) to (E).
(I) 1 g of cellulose derivative (a) and 25 ml of vinyl monomer (b) are mixed to prepare “mixture of cellulose derivative (a) and vinyl monomer (b)” and left at 25 ° C. for 1 hour. To do.
(B) The mass (W ₀ ) of the wire mesh (100 mesh) is weighed, and the “mixture of cellulose derivative (a) and vinyl monomer (b)” is filtered using this wire mesh.
(C) The weight of the cellulose derivative (a) swollen with the vinyl monomer (b) (including the wire mesh) (W ₁ ) was weighed with the cellulose derivative (a) remaining on the wire mesh, and swollen with the vinyl monomer (b). The mass (W ₁ -W ₀ ) of the cellulose derivative (a) is determined.
(D) After drying the cellulose derivative (a) swollen with the vinyl monomer (b), the mass (including the wire mesh) (W ₂ ) was weighed to remove the vinyl monomer (b) ( The mass (W ₂ −W ₀ ) of a) is determined.
(E) The swelling ratio of the cellulose derivative (a) with respect to the vinyl monomer (b) is calculated by the following formula 1.
Swelling ratio = ((W ₁ −W ₀ ) − (W ₂ −W ₀ )) ÷ (W ₂ −W ₀ ) (Formula 1)
In addition, the mass of the cellulose derivative (a) swollen with the vinyl monomer (b) obtained by this method includes the mass of the vinyl monomer (b) attached to the cellulose derivative (a).

  The swelling ratio of the cellulose derivative (a) with respect to the vinyl monomer (b) of the present invention is 2.0 or more, and more preferably 2.5 or more from the viewpoint of the transparency of the obtained resin molding. 3.0 or more is more preferable, and 3.5 or more is particularly preferable. Moreover, it is preferable that the swelling rate of the cellulose derivative (a) with respect to the vinyl monomer (b) of this invention is 25 or less.

  As a combination of the cellulose derivative (a) and the vinyl monomer (b) in which the swelling ratio of the cellulose derivative (a) with respect to the vinyl monomer (b) of the present invention is 2 or more, The acetate and vinyl monomer (b) are preferably (meth) acrylate monomers, the cellulose derivative (a) is cellulose diacetate, and the vinyl monomer (b) is methyl (meth) acrylate. More preferably, the cellulose derivative (a) is cellulose diacetate, and the vinyl monomer (b) is more preferably methyl acrylate.

  The mixture of the present invention can be prepared by a known kneading method for the cellulose derivative (a) and the vinyl monomer (b). From the viewpoint of the uniformity of the mixture and the encapsulation in the mold, the mixture of the present invention takes 30 minutes or more while heating and kneading the vinyl monomer (b), and the cellulose derivative (a) is added little by little. The method of adding is preferred.

  The content of the cellulose derivative (a) and the vinyl monomer (b) in the mixture of the present invention is the cellulose derivative (a) 1 in the total 100% by mass of the cellulose derivative (a) and the vinyl monomer (b). It is ˜80 mass%, and the vinyl monomer (b) is 20 to 99 mass%.

  As a content rate of a cellulose derivative (a), it is preferable that it is 70 mass% or less from a viewpoint of the swelling property of the mixture of a cellulose derivative (a) and a vinyl monomer (b), and the enclosure to a type | mold, 50 masses % Or less is more preferable, and 35% by mass or less is still more preferable. Further, from the viewpoint of heat resistance of the obtained resin molded body, it is preferably 3% by mass or more, more preferably 10% by mass or more, further preferably 20% by mass or more, and more preferably 30% by mass or more. It is particularly preferred that

  The resin molded body of the present invention can be obtained by cast polymerization of a mixture containing a cellulose derivative (a) and a vinyl monomer (b).

  In the cast polymerization of the present invention, a mixture containing a cellulose derivative (a) and a vinyl monomer (b) is added with a polymerization initiator and, if necessary, additives such as a chain transfer agent and a crosslinking agent. Then, it can be carried out by sealing in a mold and heating, cooling, light irradiation, or the like.

  As a type | mold, it can set suitably according to the use of the resin molding obtained, for example, shapes, such as a film and a sheet | seat, are mentioned. Specifically, a mixture containing a cellulose derivative (a) and a vinyl monomer (b) is encapsulated between two glass plates or metal plates and polymerized to obtain a film-shaped or sheet-shaped resin molded body. Method, two continuous mirror surface stainless steel belts are arranged one above the other, a mixture containing a cellulose derivative (a) and a vinyl monomer (b) is injected between the belts, polymerization is performed, and a film or sheet resin molding The method of obtaining a body is mentioned.

  As the polymerization method, a known polymerization method can be used, and examples thereof include radical polymerization, anionic polymerization, cationic polymerization, and transition metal catalyst polymerization.

The polymerization temperature can be appropriately set depending on the type of the vinyl monomer (b), the polymerization initiator, etc., but is generally 0 to 150 ° C., and can be obtained as the polymerization conversion rate of the vinyl monomer (b). It is preferable that it is 50-100 degreeC from a viewpoint of the heat history reduction of a resin molding.
The polymerization time can be appropriately set depending on the vinyl monomer (b), the type of polymerization initiator, and the like, but is generally 1 to 10 hours.

Examples of the polymerization initiator include organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, and t-butyl peroxybenzoate; Persulfates such as potassium persulfate and ammonium persulfate; azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile; depending on the combination of the organic peroxide or the persulfate and a reducing agent Redox type initiators may be mentioned.
These polymerization initiators may be used alone or in combination of two or more.

Examples of the chain transfer agent include mercaptans such as octyl mercaptan and dodecyl mercaptan.
These chain transfer agents may be used individually by 1 type, and may use 2 or more types together.

Examples of the crosslinking agent include polyfunctional vinyl monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate. . Among these crosslinking agents, ethylene glycol di (meth) acrylate and 1,3-butylene glycol di (meth) acrylate are preferable.
These crosslinking agents may be used individually by 1 type, and may use 2 or more types together.
Use of a crosslinking agent is impossible in melt molding, and is very effective in the present invention in which a resin molded body is obtained by cast polymerization. When a cross-linking agent is used, the resulting resin molded body is excellent in heat resistance and dimensional stability.
As a usage-amount of a crosslinking agent, it is preferable that it is 0.001-10 mass parts with respect to 100 mass parts of vinyl monomers, and it is preferable that it is 0.1-1 mass parts.
When the amount of the crosslinking agent used is 0.001 part by mass or more, the resulting resin molded body is excellent in heat resistance and dimensional stability. Moreover, it is excellent in the softness | flexibility of the resin molding obtained as the usage-amount of a crosslinking agent is 10 mass parts or less.

  Examples of other additives include antioxidants; light stabilizers; fillers such as glass fibers, carbon fibers, talc, calcium carbonate, kenaf, and bacterial cellulose; and dyes and pigments.

  The resin molded product obtained by the production method of the present invention is excellent in transparency, flexibility, heat resistance, and dimensional stability, and therefore is suitably used in various applications such as automobiles, home appliances, OA equipment parts, agricultural materials, and the like. Can do.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. “Parts” and “%” in the examples represent “parts by mass” and “% by mass”, respectively.
Various physical properties in Examples and Comparative Examples are evaluated by the following methods.

(1) Swelling ratio of cellulose derivative (a) with respect to vinyl monomer (b) (b) 1 g of cellulose derivative (a) and 25 ml of vinyl monomer (b) are mixed to obtain “cellulose derivative (a) and vinyl Monomer (b) mixture ”was prepared and allowed to stand at 25 ° C. for 1 hour.
(B) The mass (W ₀ ) of the wire mesh (100 mesh) was weighed, and the “mixture of cellulose derivative (a) and vinyl monomer (b)” was filtered using this wire mesh.
(C) The weight of the cellulose derivative (a) swollen with the vinyl monomer (b) (including the wire mesh) (W ₁ ) was weighed with the cellulose derivative (a) remaining on the wire mesh, and swollen with the vinyl monomer (b). The mass (W ₁ -W ₀ ) of the cellulose derivative (a) was determined.
(D) After drying the cellulose derivative (a) swollen with the vinyl monomer (b), the mass (including the wire mesh) (W ₂ ) was weighed to remove the vinyl monomer (b) ( The mass (W ₂ −W ₀ ) of a) was determined.
(E) The swelling ratio of the cellulose derivative (a) with respect to the vinyl monomer (b) was calculated by the following formula 1.
Swelling ratio = ((W ₁ −W ₀ ) − (W ₂ −W ₀ )) ÷ (W ₂ −W ₀ ) (Formula 1)

(2) Mixing state of mixture The mixing state of the obtained mixture was visually observed and judged according to the following criteria.
○: Uniform.
Δ: Slightly non-uniform.
X: It was nonuniform.

(3) Transparency (total light transmittance)
The total light transmittance of the obtained resin molding (thickness 0.5 mm) was measured according to JIS-K7261-1.

(4) Flexibility, heat resistance A test piece (thickness 0.5 mm, width 4 mm, length 15 mm) is prepared from the obtained resin molded body, and a dynamic viscoelasticity measuring device (model name “DMS200”, Seiko Instruments Inc.) The storage elastic modulus was measured under the conditions of tensile mode, frequency 1 Hz, distance between chucks 10 mm, and heating rate 5 ° C./min.
The flexibility of the obtained resin molding was determined according to the following criteria.
A: Storage elastic modulus at 60 ° C. is 0.1 GPa or less.
○: The storage elastic modulus at 60 ° C. is higher than 0.1 GPa and lower than 2 GPa.
(Triangle | delta): The storage elastic modulus in 60 degreeC is 2 GPa or more.
The heat resistance of the obtained resin molding was determined according to the following criteria.
A: The storage elastic modulus at 200 ° C. was 1/10 or less of the storage elastic modulus at 60 ° C.
○: The storage elastic modulus at 150 ° C. was 1/10 or less of the value at 60 ° C., but the storage elastic modulus at 200 ° C. was too low to be measured.
X: The storage elastic modulus at 150 ° C. was too low to be measured.

(5) Dimensional stability (linear expansion coefficient)
A test piece (thickness 0.5 mm, width 4 mm, length 15 mm) was prepared from the obtained resin molding, and a thermomechanical analyzer (model name “TMA / SS6100”, manufactured by Seiko Instruments Inc.) was used. The linear expansion coefficient was calculated by the following formula 2 under the conditions of tensile mode, tensile stress 49 mN, chuck distance 10 mm, temperature 20 to 150 ° C., and temperature rising rate 5 ° C./min.
Linear expansion coefficient (ppm) = {Chuck distance change (mm) ÷ Chuck distance initial value (mm)} ÷ Temperature change (° C.) × 10 ⁶ (Formula 2)
In addition, the distance change between chuck | zipper was taken as the maximum value at the temperature change of 50 degreeC.

[Example 1]
75 parts of methyl acrylate was added to the flask, the temperature was raised to 50 ° C., and 25 parts of cellulose diacetate (trade name “L-20”, manufactured by Daicel Chemical Industries, Ltd., acetylation degree 55%) was added while stirring. Small portions were added to prepare a uniform mixture. Further, 0.5 part of ethylene glycol dimethacrylate and 0.5 part of t-butylperoxy-2-ethylhexanoate were added to the flask, and after stirring, degassed under reduced pressure, and two glass flat surfaces It enclosed between board | substrates (space | interval 0.5mm), and it heated up gradually so that the content might not foam in a heating apparatus, and after the temperature in a heating apparatus reached | attained 60 degreeC, it hold | maintained for 4 hours. Then, it heated up at 80 degreeC and hold | maintained for 4 hours, superposition | polymerization was completed, and the resin molding (film of thickness 0.5mm) was obtained.

[Examples 2-3]
The procedure was the same as in Example 1 except that the mixture was changed as shown in Table 1.

[Comparative Examples 1-3]
Except that the mixture was as shown in Table 1, preparation of the mixture was attempted in the same manner as in Example 1. However, a uniform mixture was not obtained, and cast polymerization could not be performed.

[Comparative Examples 4 to 5]
The procedure was the same as in Example 1 except that the mixture was changed as shown in Table 1.

[Comparative Example 6]
In a reaction vessel equipped with a stirrer, a cooling tube, a heating device, a temperature sensor and a quantitative supply device, 700 parts of ion exchange water, 0.1 part of a potassium salt of a copolymer of methacrylic acid and methyl methacrylate, 25 parts of cellulose diacetate (Trade name “L-20”, manufactured by Daicel Chemical Industries, Ltd., acetylation degree 55%). While stirring, the temperature was raised to 60 ° C., 75 parts of methyl acrylate, 0.5 part of ethylene glycol dimethacrylate, 0.3 part of t-butylperoxy-2-ethylhexanoate, 0 part of t-butylperoxybenzoate .15 parts of the mixture was added to the reaction vessel over 6 hours. The mixture was further stirred for 1 hour, heated to 90 ° C. and stirred for 2 hours, and then cooled, and the solid was filtered, washed and dried to obtain a polymer.
Molding of the obtained polymer was attempted by melt molding, but the melt flow rate was less than 0.1 g / 10 min (conforming to JIS K7210, load 10 kg, temperature 280 ° C.), the melt fluidity was low, and the resin molded body Could not get. When the molding temperature was 280 ° C. or higher, the polymer deteriorated remarkably, and the temperature could not be raised to 280 ° C. or higher.

[Reference Examples 1-2]
As a reference example, a commercially available soft acrylic film (trade name “HBS010”, manufactured by Mitsubishi Rayon Co., Ltd., thickness 500 μm) and a commercially available polyester film (trade name “E5000”, manufactured by Toyobo Co., Ltd., thickness 500 μm) are resin-molded. Used as a body.

Table 1 shows the evaluation results of the resin moldings obtained in Examples 1 to 3, Comparative Examples 4 to 5 and Reference Examples 1 and 2.
The resin molded body obtained in Comparative Example 4 was inferior in mechanical strength and could not be subjected to thermomechanical analysis. Moreover, the resin molding obtained in Comparative Example 5 was inferior in mechanical strength and flexibility, and could not perform dynamic viscoelasticity measurement and thermomechanical analysis.

Abbreviations in Table 1 are shown below.
CDA: cellulose diacetate (trade name “L-20”, manufactured by Daicel Chemical Industries, Ltd., acetylation degree 55%)
CTA: cellulose triacetate (trade name “LT-35”, manufactured by Daicel Chemical Industries, Ltd., acetylation degree 61%)
MA: methyl acrylate MMA: methyl methacrylate ST: styrene

As shown in Table 1, the resin molded bodies obtained in Examples 1 to 3 were excellent in transparency, flexibility, heat resistance, and dimensional stability.
In Comparative Example 1 in which the content of the cellulose derivative (a) is too high and in Comparative Examples 2 to 3 in which the swelling ratio of the cellulose derivative (a) with respect to the vinyl monomer (b) is too low, the mixed state becomes uneven and casting is performed. Polymerization could not be performed.
The resin moldings obtained in Comparative Examples 4 to 5 containing no cellulose derivative (a) were inferior in flexibility and heat resistance.
The polymer produced by suspension polymerization obtained in Comparative Example 6 had low melt flowability and could not be melt-molded, and a resin molded body could not be obtained.
The resin molded body of Reference Example 1, which is a commercially available acrylic film, was inferior in heat resistance. The resin molded product of Reference Example 2, which is a commercially available polyester film, was inferior in transparency and flexibility.

  The resin molded product obtained by the production method of the present invention is excellent in transparency, flexibility, heat resistance, and dimensional stability, and thus is suitably used in various applications such as automobiles, home appliances, OA equipment parts, and agricultural materials. be able to. Moreover, in the resin material, substitution from the raw material derived from petroleum to the raw material derived from non-petroleum can be promoted.

Claims (2)

Cellulose diacetate (a) 1 to 80% by mass and (meth) acrylate monomer (b) 20 to 99% by mass (provided that the total of cellulose diacetate (a) and (meth) acrylate monomer (b) is the mixture consisting of 100 wt%) a method for producing a resin molded product obtained by casting polymerization,
The manufacturing method of the resin molding whose swelling rate of the cellulose diacetate (a) with respect to a (meth) acrylate monomer (b) is 2.0 or more.   The method for producing a resin molded article according to claim 1, wherein the mixture is obtained by cast polymerization by further adding a crosslinking agent to the mixture.