JP5618153B2 - Resin composition and molded body - Google Patents

Description

The present invention relates to a resin composition and a molded body .

  The biodegradable resin means that the resin is decomposed into water and carbon dioxide by the action of microorganisms, water, sunlight and the like. Since the decomposition product to be purified at this time is used again for the growth of plants, it is reviewed as a carbon neutral material from the viewpoint of global warming. In addition, by making the biodegradable resin 100% plant-derived material, it is possible to reduce the petroleum-derived material. At present, there is an active movement to replace plastics such as packaging materials, household appliances, and automobiles with plant-derived resins (bioplastics).

Specific examples of the plant-derived resin include polylactic acid: PLA (Polylactic Acid) produced by chemical polymerization using lactic acid obtained by fermenting sugars such as potato, sugarcane, and corn as a monomer. , Starch-based esterified starch, microorganism-produced resin that is a polyester produced by microorganisms in the body: PHA (PolyHydroxy Alkanoate), 1,3-propanediol obtained by fermentation, and petroleum-derived terephthalic acid as raw materials And PTT (Poly Trimethylene Telephthalate). In particular, polylactic acid has been widely studied as a biodegradable resin (see Patent Document 1).
In addition, PBS (Poly Butylene Succinate) is currently used as a raw material derived from petroleum, but in the future, research to produce it as a plant-derived resin has been developed, and succinic acid, one of the main raw materials, has been developed. Developments have been made on technologies that are derived from plants.

  Lignin is also attracting attention as a plant-derived biodegradable resin obtained from woody materials. However, lignin sulfonate is mentioned as lignin which can be easily obtained in Japan, but it is water-soluble and hardly soluble in organic solvents. Therefore, the current situation is that the compatibility with other resins is poor and the utilization as a biomass material is not progressing.

JP 2005-60556 A

In the present invention, it is an object to provide a resin composition having a biodegradation rate suitable for use by reducing petroleum-derived materials from the viewpoint of reducing environmental burden. Moreover, it aims at providing the molded object with the favorable external appearance using a resin composition.

If we can extract lignin in a form soluble in organic solvents, we believe that the biodegradation rate can be controlled by combining it with biomass materials with different biodegradation rates,
As a result of investigation, the present invention has been achieved.
The present invention is as follows.
(1) A resin composition used for a molded product for agricultural or civil engineering applications, wherein the composition comprises a lignin and a biodegradable resin component other than lignin, the lignin containing The amount is 1 to 50% by mass as a nonvolatile content, and the lignin is obtained by separating and dissolving the cellulose component and the hemicellulose component by a separation technique using water, and the weight average molecular weight is A resin composition that is 100 to 7000 and can control the biodegradation rate by being soluble in an organic solvent .
(2 ) Lignin was obtained by separating water from a cellulose component and hemicellulose component by a steam explosion method that injects water vapor into the plant material and instantly releases the pressure to explode the plant material and dissolves it in an organic solvent. The resin composition according to (1 ), which is a product.
( 3 ) The resin composition as described in (1) or (2) above, further comprising a plasticizer.
(4) The resin composition according to any one of claims 1 to 3, wherein the biodegradable resin is polylactic acid or polyethylene succinate.
( 5 ) A molded article used for agriculture or civil engineering obtained by molding the resin composition according to any one of (1) to (4) .
(6) molded article, the molded body according to the a Resid over preparative such cured into a sheet (5).

ADVANTAGE OF THE INVENTION According to this invention, the biodegradable resin composition and molded object for agricultural and civil engineering use with which the reduction effect of a fossil resource usage and the reduction | decrease effect of the discharge | emission of a carbon dioxide are acquired and it is suitable for environmental load reduction by biodegradation Can be provided.
According to the present invention, biodegradable resin compositions having various biodegradation rates can be provided by adding lignin. Further, it is possible to provide a good appearance molded article using the resin composition.

Hereinafter, the present invention will be described in more detail.
The present invention is a resin composition containing lignin and a resin component, wherein the lignin is soluble in an organic solvent and contains 1 to 50% by mass of lignin as a nonvolatile content.
Moreover, this invention is a sheet | seat formed by hardening | curing the said resin composition in a sheet form, and the resin composition and sheet | seat of this invention are suitable for agriculture or a civil engineering use.
In the resin composition, lignin is preferably contained in an amount of 1 to 40% by mass, and more preferably 1 to 35% by mass. If it exceeds 50% by mass, the strength and flexibility of the resin composition and the sheet may be deteriorated. Moreover, there exists a possibility that the influence which lignin has on the biodegradation rate may fall that it is less than 1 mass%.

The weight average molecular weight of the lignin used in the present invention is preferably 100 to 7000, more preferably 200 to 5000, and particularly preferably 500 to 4000 in terms of polystyrene. When the weight average molecular weight of lignin exceeds 7000, there exists a possibility that the solubility to an organic solvent may fall. If the weight average molecular weight is less than 100, there is a possibility that a resin composition and sheet for agricultural / civil engineering applications utilizing the structure of lignin cannot be obtained.
The weight average molecular weight was measured by gel permeation chromatography (GPC), and a value converted to standard polystyrene was used.

  There is no restriction | limiting in particular in the raw material of lignin used by this invention. Conifers such as cedar, pine and cypress, broad-leaved trees such as beech, bamboo, rice straw, bagasse and the like are used. Examples of methods for separating and taking out lignin from trees include the kraft method, the sulfuric acid method, and the explosion method. Currently, most of the lignin produced in large quantities is obtained as a residue during the production of cellulose, which is a raw material for paper and bioethanol. In addition, there are alkali lignin, organosolv lignin, solvolysis lignin, wood treated with filamentous fungi, dioxane lignin and milled wood lignin, explosive lignin and the like. As for the lignin used in the present invention, the above lignin can be used as long as the lignin is soluble in an organic solvent, regardless of the extraction method.

  When lignin is taken out, components such as cellulose and hemicellulose other than lignin may be contained to some extent. In addition, lignin derivatives produced by acetylation, methylation, halogenation, nitration, sulfonation, reaction with sodium sulfide or hydrogen sulfide, and the like are included in the category.

As a method for obtaining lignin as a main raw material, a method using a separation technique using water is preferable. The lignin used is preferably a lignin obtained by separating it from a cellulose component and a hemicellulose component by a treatment method using only water and dissolving it in an organic solvent. Moreover, as a method for obtaining lignin, the steam explosion method is more preferable. The steam explosion method crushes plants in a short time by hydrolysis with high-temperature and high-pressure steam and a physical crushing effect by instantaneously releasing the pressure.
The conditions for steam explosion are not particularly limited. Usually, the raw material is placed in a pressure vessel for a steam explosion apparatus, 3-4 MPa of steam is injected, left for 1-15 minutes, and then the pressure is released immediately. Explode. The organic solvent-soluble lignin is also referred to as steam explosion lignin. The raw material is not particularly limited as long as lignin can be extracted, and examples include cedar, bamboo, rice straw, straw, hinoki, acacia, willow, poplar, bagasse, corn, sugarcane, rice grain, eucalyptus, and Eliansus. . This method is a clean separation method because only water is used without using sulfuric acid, sulfite or the like, compared with other separation methods such as sulfuric acid method and kraft method. In this method, lignin containing no sulfur atom in the lignin or lignin having a low content of sulfur atoms can be obtained. Usually, the content of sulfur atoms in lignin is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less. When the sulfur atom content is increased, hydrophilic sulfonic acid groups are increased, so that the solubility in an organic solvent is lowered. Furthermore, the present inventors have found that the molecular weight of lignin can be controlled by extracting lignin from an explosion with an organic solvent.

  The organic solvent used in the extraction of lignin used in the present invention is one or a mixture of two or more kinds of alcohol solvents, a hydrous alcohol solvent in which alcohol and water are mixed, another organic solvent, or a hydrous organic solvent in which water is mixed. Can be used. It is preferable to use ion exchange water as water. The water content of the mixed solvent with water is preferably 0 to 70% by mass. Since lignin has low solubility in water, it is difficult to extract lignin using only water as a solvent. Moreover, it is possible to control the weight average molecular weight of the lignin obtained by selecting the solvent to be used.

  Examples of the organic solvent alcohol to be extracted include monools such as methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, n-hexanol, benzyl alcohol, and cyclohexanol, and ethylene glycol, diethylene glycol, Examples include polyols such as 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, glycerin, and triethanolamine. Further, an alcohol obtained from a natural substance is more preferable from the viewpoint of reducing environmental load. Specifically, methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, ethylene obtained from natural substances Examples include glycol, glycerin, and hydroxymethylfurfural.

Examples of the resin component used in the present invention include polyethylene, polypropylene, polyolefin, polystyrene, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, polyurethane, polyphenylene sulfide, polyethylene vinyl acetate copolymer, methacrylic resin, Polyamide, polyacetal, polycarbonate and the like can be mentioned. Biodegradable resins include biomass-derived polylactic acid, polyhydroxyalkanoate, starch, esterified starch, chitosan, polyhydroxybutyrate, cellulose acetate, cellulose ester, 1, 3-propanediol, polycaprolactan derived from petroleum, polyvinyl alcohol, polybutylene succinate, polyglycolic acid, polyethylene Shineto, and the like. Among the above resin components, a biodegradable resin is more preferable for improving biodegradability, and a biodegradable resin derived from biomass is particularly preferable from the viewpoint of reducing petroleum-derived substances.
In the resin composition, the content of the resin component is preferably 40 to 99% by mass, more preferably 50 to 90% by mass, and particularly preferably 60 to 80% by mass as a nonvolatile content. Moreover, 10-100 mass% is preferable, as for the ratio of the biodegradable resin in a resin component, 50-95 mass% is more preferable, and 70-90 mass% is especially preferable.

The resin composition of the present invention preferably further contains a plasticizer. Examples of the plasticizer used in the present invention include di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate and other phthalic acid derivatives, diisooctyl phthalate, and the like. Isophthalic acid derivatives, di-n-butyl adipate, adipic acid derivatives such as dioctyl adipate, maleic acid derivatives such as di-n-butyl malate, citric acid derivatives such as tri-n-butyl citrate, monobutyl itaconate, etc. Low molecular weight compounds such as itaconic acid derivatives, oleic acid derivatives such as butyl oleate, ricinoleic acid derivatives such as glycerol monoricinoleate, phosphate esters such as tricresyl phosphate and trixylenyl phosphate, polyethylene adipate, polya Polymeric plasticizers such relations are exemplified.
In the resin composition, the content of the plasticizer is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, and particularly preferably 10 to 15% by mass as a nonvolatile content.

The resin composition and sheet of the present invention may contain a fiber for the purpose of improving the strength. Examples of the fiber include plant fibers, synthetic fibers, carbon fibers, and inorganic fibers.
Moreover, in a resin composition, 1-30 mass% is preferable as a non-volatile content, and 5-20 mass% is more preferable, and 10-15 mass% is especially preferable.

In the resin composition and sheet of the present invention, various additive components, lubricants, stabilizers, antioxidants, ultraviolet absorbers, antifungal agents, fillers, mold release agents, flame retardants, and the like are blended as necessary. You can also.
Moreover, the resin composition and sheet | seat of this invention are suitable for agriculture or a civil engineering use. For example, insect-proof nets for reduced farming and pesticide-free cultivation, herbicide-free herbicide sheets, shading nets that control strong sunlight, animal nets that prevent wild animals from entering, and herbicide sheets that support organic farming in home gardens Recyclable PET bottles, aluminum cans, etc., separate resource collection bags, garbage guard nets that protect garbage from attacks by crows, stray dogs, and stray cats, breakwater scour prevention sheets and sediment prevention sheets in harbors and rivers It can be used as a sheet for continuous underground wall formwork at construction sites.

The method for producing the sheet of the present invention is not particularly limited as long as the resin composition can be cured into a sheet shape. For example, it is produced by pulverization, granulation, injection molding (molding), mold molding, inflation method, T-die method, solution casting method, calendar method and the like. The thickness of the sheet of the present invention is usually 0.1 to 2 mm, preferably 0.2 to 1.5 mm.
The resin composition of the present invention can also be used as a molded body (or molded body) other than a sheet. For example, a molded body (or molded body) is produced by an injection molding method, a mold molding method, or the like. May be.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, the scope of the present invention is not limited to these Examples.

Example 1
(Extraction of lignin)
Bamboo was used as a lignin extraction raw material. Bamboo material cut to an appropriate size was placed in a 2 L pressure vessel of a steam explosion device, 3.5 MPa of water vapor was injected and held for 4 minutes. Thereafter, the valve was rapidly opened to obtain an explosion-treated product. The explosion-treated product obtained until the pH of the cleaning solution reached 6 or more was washed with water to remove water-soluble components. Thereafter, residual moisture was removed with a vacuum dryer. The resulting dried product: 100 g of an extraction solvent (acetone) was added to 100 g, and the mixture was stirred for 3 hours, and then the fiber material was removed by filtration. The extraction solvent (acetone) was removed from the obtained filtrate to obtain lignin. The obtained lignin was a brown powder at room temperature (25 ° C.).

(Lignin analysis)
The solvent solubility was evaluated by adding 1 g of the lignin to 10 ml of an organic solvent. When it melt | dissolved easily at normal temperature (25 degreeC), it evaluated as "(circle)" when melt | dissolving at 50-70 degreeC, and (△) when it did not melt | dissolve even if heated. As a result of evaluating the solubility as acetone, cyclohexanone, tetrahydrofuran as the solvent group 1 and methanol, ethanol, and methyl ethyl ketone as the solvent group 2, the solvent group 1 was judged as “◯” and the solvent group 2 as “△”. It was.

  The content of sulfur atoms in lignin was quantified by combustion decomposition-ion chromatography. As the apparatus, an automatic sample combustion apparatus (AQF-100) manufactured by Mitsubishi Chemical Analytech Co., Ltd. and an ion chromatograph (ICS-1600) manufactured by Nippon Dionex Co., Ltd. were used. The content rate of the sulfur atom in the said lignin was 0.01 mass%. Further, the weight average molecular weight of lignin was measured by gel permeation chromatography (GPC) equipped with a differential refractometer. Polystyrene having a low polydispersity was used as a standard sample, the mobile phase was used as tetrahydrofuran, and gel packs GL-A120S and GL-A170S manufactured by Hitachi High-Technologies Corporation were connected in series as columns to perform molecular weight measurement. Its weight average molecular weight was 2400.

The hydroxyl equivalent of the lignin (organic solvent soluble lignin) obtained above was determined by measuring the hydroxyl value by acetic anhydride-pyridine method and the acid value by potentiometric titration method. The hydroxyl equivalent of acetone-extracted bamboo-derived lignin is 140 g / eq. Met.
The molar ratio (hereinafter P / A ratio) of the phenolic hydroxyl group and alcoholic hydroxyl group of lignin was determined by the following method. Lignin: 2 g of acetylation treatment was performed, the unreacted acetylating agent was distilled off, and the dried product was dissolved in deuterated chloroform. ¹ H-NMR (manufactured by BRUKER, V400M, proton fundamental frequency 400.13 MHz) ). Determine the molar ratio from the integral ratio of protons derived from acetyl groups (derived from acetyl groups bonded to phenolic hydroxyl groups: 2.2 to 3.0 ppm, derived from acetyl groups bonded to alcoholic hydroxyl groups: 1.5 to 2.2 ppm). As a result, the P / A ratio was 2.2 / 1.0.

(Example 2)
(Preparation of resin composition)
After 99 g of polylactic acid (REVODE manufactured by Zhejiang Kaisei Biological Materials Co., Ltd.), a plant-derived biodegradable resin, is charged into a kneader (Toyo Seiki Co., Ltd., Lab Plast Mill, model: 4C150) and melted. 1 g of the above lignin (organic solvent-soluble lignin; acetone extraction) was added. Therefore, a resin composition containing 1% by mass of lignin and having a plant-derived component ratio of 100% by mass was obtained.
Hereinafter, the content of lignin is in the nonvolatile content of the resin composition.
Furthermore, the resin composition was kneaded at 180 ° C. for 5 minutes, and then press molded under the conditions of 1 MPa, 180 ° C. and 5 minutes to obtain a molded body.

(Appearance evaluation)
The appearance of the obtained molded body was visually evaluated. “◯” indicates that the surface shape is smooth and suitable as a molded body, and “x” indicates that the degree of kneading of lignin is not uniform or the surface shape is poor and is not suitable as a molded body.
The appearance of the molded body of Example 2 obtained above was judged as “◯”.

(Measurement of biodegradation rate (decomposition rate) of compacts)
A section obtained by cutting the shaped body into strips was sandwiched between saran cloths and embedded in soil, and the soil water was cultured under constant temperature conditions of 50% of the maximum water volume and temperature: 60 ° C. The section taken out with time was subjected to ultrasonic cleaning to remove the surface soil, dried, and weighed to measure the biodegradation rate (decomposition rate). As a result, the decomposition rate after 80 days was 10%.

Example 3
(Extraction and analysis of lignin)
Lignin was obtained in the same manner as in Example 1 except that methanol was used as the extraction solvent. Elemental analysis and molecular weight measurement were performed in the same manner as in Example 1. As a result, the content of sulfur atoms in lignin was less than 0.2% by mass, and the weight average molecular weight was 1,900. As a result of evaluating the solvent solubility in the same manner as in Example 1, the determination was “◯” for the solvent group 1 and “◯” for the solvent group 2. The molar ratio of the phenolic hydroxyl group and alcoholic hydroxyl group of lignin (hereinafter referred to as P / A ratio) was carried out in the same manner as in Example 1.
The lignin P / A ratio was 1.6 / 1.0. As in Example 1, as a result of measuring the hydroxyl equivalent of the lignin (organic solvent-soluble lignin) obtained above, the hydroxyl equivalent was 120 g / eq. Met.

(Preparation of resin composition)
Except having used the said lignin (organic solvent soluble lignin; methanol extraction), it carried out like Example 2 and produced the resin composition of the plant origin component ratio containing 1 mass% of lignin of 100 mass%.
Further, the resin composition was kneaded at 180 ° C. for 5 minutes, and then press-molded under the conditions of 1 MPa, 180 ° C. and 5 minutes to obtain a molded body.

(Appearance evaluation and measurement of biodegradation rate (decomposition rate))
The appearance of the obtained molded body was visually evaluated in the same manner as in Example 2. The appearance of the obtained molded article of Example 3 was judged as “◯”. Further, the biodegradation rate (decomposition rate) was measured in the same manner as in Example 2. As a result, the decomposition rate after 80 days was 10%.

Example 4
A resin composition was obtained in the same manner as in Example 2 except that 50 g of lignin described in Example 1 was added and polylactic acid was changed to 50 g. The obtained resin composition contained 50% by mass of lignin, and the plant-derived component ratio was 100% by mass. As a result of producing a molded body in the same manner as in Example 2 and evaluating the appearance, it was judged as “◯”. Further, the biodegradation rate (decomposition rate) was measured in the same manner as in Example 2. As a result, the decomposition rate after 80 days was 20%.

(Example 5)
Polyethylene succinate (PES) derived from petroleum was used in place of polylactic acid except that 99 g was used, and a resin composition having a plant-derived component ratio of 1% by mass containing 1% by mass of lignin was prepared. A compact was obtained by pressing. As a result of producing a molded body in the same manner as in Example 2 and evaluating the appearance, it was judged as “◯”. Further, the biodegradation rate (decomposition rate) was measured in the same manner as in Example 2. As a result, the decomposition rate after 80 days was 95%.

(Example 6)
A resin composition was obtained in the same manner as in Example 2 except that 50 g of lignin described in Example 1 was used and 50 g of petroleum-derived polyethylene succinate (PES) was used instead of polylactic acid. The obtained resin composition contained 50% by mass of lignin, and the plant-derived component ratio was 50% by mass. As a result of producing a molded body in the same manner as in Example 2 and evaluating the appearance, it was judged as “◯”. Moreover, as a result of measuring the biodegradation rate (decomposition rate) in the same manner as in Example 2, the decomposition rate after 80 days was 50%.

(Example 7)
(Production of sheet)
Polylactic acid, which is a plant-derived biodegradable resin (REVODE manufactured by Zhejiang Haisei Biological Materials Co., Ltd.): 72 g and a mixed adipate, which is a plasticizer (DAIFATTY-101, manufactured by Daihachi Industry Co., Ltd.): 18 g 10 g of lignin (organic solvent-soluble lignin) described in Example 1 was added thereto after being poured into a Toyo Seiki Co., Ltd. Lab Plast Mill, Model 4C150) and melted. Therefore, a resin composition containing 10% by mass of lignin and having a plant-derived component ratio of 82% by mass was obtained. A sheet having a thickness of 1 mm was obtained by extruding this resin composition. As a result of evaluating the appearance of the sheet in the same manner as in Example 2, the result was “◯”. Further, the biodegradation rate (decomposition rate) was measured in the same manner as in Example 2. As a result, the decomposition rate after 80 days was 13%.

(Comparative Example 1)
A resin composition was obtained in the same manner as in Example 6 except that 52 g of lignin described in Example 1 was added and 48 g of polyethylene succinate (PES) was added. The obtained resin composition contained 52% by mass of lignin, and the plant-derived component ratio was 52% by mass. As a result of producing a molded body and evaluating the appearance in the same manner as in Example 2, the result was “x”. Moreover, as a result of measuring the biodegradation rate (decomposition rate) in the same manner as in Example 2, the decomposition rate after 80 days was 50%.

(Comparative Example 2)
The same procedure as in Example 2 was conducted except that lignin sulfonate (Vanilex N, high-purity partially desulfurized sodium lignin sulfonate, manufactured by Nippon Paper Industries Co., Ltd.) was used as the lignin. As a result, since lignin sulfonate was water-soluble and hardly soluble in organic solvents, lignin sulfonate and polylactic acid were not compatible, and a resin composition could not be obtained.

(Comparative Example 3)
The same procedure as in Example 2 was performed except that lignin sulfonate (Sun extract P321, magnesium lignin sulfonate, manufactured by Nippon Paper Industries Co., Ltd.) was used as lignin. As a result, lignin sulfonate and polylactic acid were not compatible with each other, and a resin composition could not be obtained.

As shown in the Examples, it can be seen that when the content of lignin is 1 to 50% by mass, the surface shape of the molded body and the sheet becomes smooth and the appearance is good. In addition, as shown in the examples and comparative examples, by changing the lignin content in the resin, the biodegradation rate is accelerated with polylactic acid that is difficult to decompose in soil, and the degradation rate with polyethylene succinate that is easy to biodegrade. Suppressed. Thus, it turned out that the biodegradation rate (decomposition rate) of a molded object or a sheet | seat can be controlled by changing a plant-derived component ratio.

Claims (6)

A resin composition used for a molded article for agriculture or civil engineering, wherein the composition comprises lignin and a biodegradable resin component other than lignin , wherein the content of lignin is The non-volatile content is 1 to 50% by mass, and the lignin is obtained by separating and dissolving the cellulose component and the hemicellulose component by a separation technique using water, and the weight average molecular weight is 100 to 7000. A resin composition that can control the biodegradation rate by being soluble in an organic solvent. The lignin was obtained by separating the cellulose component and hemicellulose component by the steam explosion method, in which steam is injected into the plant material and the plant material is blasted by instantaneously releasing the pressure, and dissolved in an organic solvent. The resin composition according to claim 1 . Further resin composition according to claim 1 or 2, characterized in that it comprises a plasticizer. The resin composition according to any one of claims 1 to 3, wherein the biodegradable resin is polylactic acid or polyethylene succinate. The molded object used for agriculture or civil engineering obtained by shape | molding the resin composition in any one of Claims 1-4 . Molded article, molded article according to claim 5 which is Resid over preparative such cured into a sheet.