JPH11152410A - Resin composition including lignin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition excellent in antibacterial properties, moldability, heat resistance useful for household electric appliance such as inexpensive mouse pads, household utensils such as sanitary goods and the like by making the composition include thermoplastic resins and lignin in a specific ratio using an antibacterial agent originating from stably obtainable natural substances. SOLUTION: This composition includes (A) 99.9-70 wt.% of the thermoplastic resins such as styrene based resins (e.g.; high inpact polystyrene and the like) preferably having 50,000-800,000 of weight average molecular weight, (B) 0.1-30 wt.%. of the lignin compounds (e.g.; alkali lignin and the like). The composition is useful for a wide variety of uses such as various equipments for office automation, building materials, car parts, medical supplies, miscellaneous goods and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic resin composition having excellent antibacterial properties and moldability.

[0002]

2. Description of the Related Art Thermoplastic resins have been used in a wide range of fields such as electronic and electric fields, home electric appliances fields, automobile fields, sanitary fields such as toilet seats, kitchens and bathrooms, miscellaneous goods, and building materials. It has been pointed out that bacteria and mold proliferate in the products used in these products and have an adverse effect on the human body. For example, damage caused by O-157 is new to memory.

As a method for imparting antibacterial property to a thermoplastic resin, there is a method in which an antibacterial agent is kneaded into a thermoplastic resin or a method in which an antibacterial agent is applied to the surface of a thermoplastic resin product.
At present, as an antibacterial agent, an inorganic antibacterial agent is mainly used for kneading, while an organic antibacterial agent is mainly applied to a product in a liquid state. Representative examples of inorganic antibacterial agents include zeolites and synthetic minerals substituted with a metal such as silver, and examples of organic antibacterial agents include chlorohexidine and quaternary ammonium salts. As organic antibacterial agents derived from natural products, hinokitiol, wasauro (active ingredient; allyl isothiocyanate), wasabi, ginger,
Despite the advantages of being derived from natural products, they generally do not withstand the processing temperature of the resin, are difficult to obtain due to limited supply, and have other additives to improve compatibility with the resin. There was a problem that an agent had to be added.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a low-cost resin composition having an antibacterial property and an improved moldability by using a natural product-derived antibacterial agent which can be supplied stably. To provide.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, by adding a lignin compound to a thermoplastic resin, a resin composition having excellent antibacterial properties and good moldability has been obtained. The present inventors have found that a product can be obtained, and have accomplished the present invention. That is, the present invention is as follows.

1) 99.9 to 70% by weight of a thermoplastic resin,
A resin composition comprising a lignin compound at 0.1 to 30% by weight. 2) The resin composition as described in 1 above, wherein the thermoplastic resin is a styrene resin. 3) An antibacterial resin composition comprising the resin composition described in 1 or 2 above.

Hereinafter, the present invention will be described in detail. The thermoplastic resin (A) used in the present invention can be arbitrarily selected from thermoplastic resins used as ordinary molding materials. Such a thing, for example, styrene resin, olefin resin, methacrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyamide resin, polyester resin, polyurethane resin, polycarbonate resin, polyacetal resin, fluorine resin and Examples include various thermoplastic elastomers,
Among these, styrene-based resins, olefin-based resins, methacryl-based resins, and polyvinyl chloride-based resins are preferred, and styrene-based resins are particularly preferred.

As the styrene resin, those generally used for molding, for example, styrene homopolymer (PS), high impact polystyrene (HIPS), methyl methacrylate / styrene copolymer (MS) Heat resistance obtained by copolymerizing methyl methacrylate-butadiene-styrene copolymer (MBS), styrene-maleic anhydride copolymer (SMA), styrene-methacrylic acid copolymer (SMAA), α-methylstyrene or maleimide Styrene resin, furthermore, styrene / acrylonitrile copolymer resin, α-methylstyrene / acrylonitrile copolymer resin, polyphenylene ether resin and the like.

Here, the styrene / acrylonitrile copolymer resin includes acrylonitrile / styrene copolymer (AS), acrylonitrile / styrene / butadiene copolymer (ABS), and acrylonitrile / styrene / acrylic rubber copolymer (AAS). Acrylonitrile / styrene / chlorinated polyethylene copolymer (ACS), acrylonitrile / styrene / ethylene / propylene rubber copolymer (AES), acrylonitrile / styrene / ethylene / vinyl acetate copolymer, α-methylstyrene or maleimide Including α-methylstyrene / acrylonitrile copolymer resin, the styrene portion of the styrene / acrylonitrile copolymer resin is replaced by α-methylstyrene.
-Methylstyrene / acrylonitrile copolymer resin. Among them, PS, HI
It is more effective for PS, AS and ABS resins.

These styrene resins have a weight average molecular weight (Mw) of 1,000 to 1,000,000, preferably 10,000 to 1,000,000, and more preferably 50,000 to 800,000. Those in the range are preferred. Further, these thermoplastic resins may be used alone or in combination of two or more kinds as a polymer alloy. Styrene resins having a branched structure are also preferably used.

The olefin resins mentioned above are those generally used for molding, for example, polyethylene resins such as ultra-low-density polyethylene, low-density polyethylene, linear low-density polyethylene, medium-low-density polyethylene, and high-density polyethylene. Having a vinyl acetate content of 0.1 to 25
% By weight of ethylene / vinyl acetate copolymer, 0.1 to 25% by weight of ethylene / acrylic acid copolymer, propylene homopolymer, ethylene content of 2 to 4%
0 mol% of a crystalline propylene / ethylene block copolymer, a crystalline ethylene / propylene random copolymer having an ethylene content of 0.5 to 10 mol%, polybutene, ethylene / propylene rubber, ethylene / propylene / diene rubber, etc. Can be mentioned.

Examples of the above methacrylic resin include, in addition to methyl methacrylate homopolymer, methyl methacrylate and other monomers such as styrene, α-methylstyrene, acrylonitrile, various acrylates and methacrylates. Methacrylic resin which has improved various performances, and furthermore, methyl methacrylate, styrene, acrylonitrile, various acrylic acid esters in polymers mainly composed of acrylates and methacrylic esters or polymers mainly composed of butadiene Impact-resistant methacrylic resin obtained by graft copolymerization of methacrylic acid ester or methacrylic acid ester.

Examples of the above polyvinyl chloride resin include, in addition to vinyl chloride homopolymer, vinyl chloride, ethylene, propylene, acrylonitrile, vinylidene chloride,
MBS resin, ABS resin, copolymer obtained by polymerizing vinyl acetate or the like as a comonomer, or polyvinyl chloride,
Examples thereof include nitrile rubber, chlorinated polyethylene, EVA-PVC graft copolymer, and modified polyvinyl chloride resin to which various plasticizers are added.

These thermoplastic resins have a weight average molecular weight (Mw) of 1,000 to 1,000,000, preferably 10,000 to 1,000,000, and more preferably 50,000 to 800,000. Those in the range are preferred. Further, these thermoplastic resins may be used alone or in combination of two or more kinds as a polymer alloy.

In the present invention, (B) the lignin compound is 0.1 to 30% by weight, preferably 0.5 to 15% by weight,
More preferably, it is used in an amount of 1 to 10% by weight. If the addition amount is too small, there is no antibacterial effect, and if the addition amount is too large, the strength and the like are reduced, and the improvement of the antibacterial effect is leveled off. The lignin compound is lignin and its derivatives present in wood with cellulose. Lignin is bound to cellulose and hemicellulose and needs to be separated and taken out of these. Examples of lignin compounds include acid lignin (lignin sulfate, lignin hydrochloride, etc.), copper oxide ammonia lignin, lignin periodate, and lignin obtained by a method of dissolving carbohydrates and separating lignin as insoluble residues. Alkaline lignin, lignosulfonic acid, thiolignin, chlorlignin, and lignin obtained by a method of dissolving and dissolving with an organic reagent, Browns natural lignin, bojorkman lignin, dioxane lignin obtained by a method of dissolving and separating lignin with an organic reagent Hydrotropic lignin, alcohol lignin, phenol lignin, lignin acetate and the like.

At the time of taking out, components other than some lignin, such as cellulose and hemicellulose, may be contained. In addition, lignin derivatives produced by acetylation, methylation, halogenation, nitration, sulfonation, reaction with sodium sulfide or hydrogen sulfide, or the like, of these lignins are also included. Further, acid precipitated polymer lignin described in JP-A-59-48087, polymer processing, 46
Lignins described in (3), 122 (1997) are also included in the lignin compound of the present invention.

Examples of products from the catalog of Nippon Paper Industries Co., Ltd. include sun extract P201 (calcium ligninsulfonate), P321 (magnesium ligninsulfonate), P252 (magnesium ligninsulfonate),
SCP (modified calcium lignin sulfonate), NDP
(Modified sodium ligninsulfonate), ODP (modified sodium ligninsulfonate), HW, N, RN, R
NAP (above, high-purity partially desulfonated sodium ligninsulfonate), CP (high-purity high-molecular-weight calcium ligninsulfonate), NP (high-purity high-molecular-weight sodium ligninsulfonate), DP (high-purity modified sodium ligninsulfonate), etc. Is mentioned.

Although a liquid product may be used, a powder product is more preferable. Industrial products of these lignin compounds are generated when raw materials for paper and cellulose fibers are produced from pulp. A lignin compound generated when NaOH or Na ₂ O is added to pulp during the production of paper raw material is called KP lignin, and a lignin compound generated when a cellulose fiber raw material is generated from pulp is called SP lignin. Both compounds are effectively used in the present invention.

The lignin compound usually contains several% of water, and is removed and melt-kneaded. Alternatively, when molding such as foaming, the contained water can be used as a foaming agent as it is. When removing, there are a method of drying the lignin compound itself with a vacuum dryer and a hot air dryer, a method of kneading the resin with the resin in an extruder in an undried state, and devolatilizing from a vent of the extruder.

In the present invention, if necessary, various additive components, plasticizers (mineral oil, silicone oil, etc.), lubricants, stabilizers, antioxidants, ultraviolet absorbers, flame retardants, release agents, inorganic Fillers, organic fillers, and the like can be blended at the time of polymerizing the polymer component or at the time of forming the polymer molded article. Further, other known antibacterial agents and fungicides may be used in combination.

The resin composition of the present invention thus obtained can be obtained by a known method generally used for molding a thermoplastic polymer, such as injection molding, extrusion molding, blow molding, inflation molding, vacuum molding and the like. The molded article is formed into various molded articles by the above method. Further, after being formed into a film, a biaxially stretched film, a sheet, a foamed sheet, a foamed bead or the like, it is formed into a desired formed body. At that time, the molding temperature is preferably 300 ° C. or lower, more preferably 270 ° C. or lower, and most preferably 250 ° C. or lower.

The resin composition of the present invention can be used in a wide range of applications, for example, various OA devices and home electric appliances (mouse pads, CDs, etc.).
-ROM packaging, storage case for floppy disk magazine attachment, household goods (toilet seats, various sanitary products such as wash basin parts, bath lids, foam boards under the sink, etc.)
In addition, it is suitable for a wide range of uses such as building materials, vehicle parts, daily necessities, toys, tableware, various packagings, medical supplies, and miscellaneous goods. It can also be expected to be used for fungicidal properties.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples. In addition, the measuring method of each physical property and the raw material used are shown below. <Antibacterial property> A flat foamed molded article of the resin composition (thickness 1.5
mm) was cut into 50 mm × 50 mm, and the surface of the molded body was wiped clean with gauze impregnated with ethanol, and left at 24 ° C. in an atmosphere of 23 ° C. and 60% relative humidity for 24 hours to obtain a sample for an antibacterial activity test. Bacterial solution 0.5
ml and inoculated with a 45 mm x 45 mm polyethylene film, and then stored at 37 ° C.
After 4 hours, surviving bacteria are washed out with an SCDLP medium (manufactured by Nippon Pharmaceutical Co., Ltd.). The number of surviving bacteria was measured from the washed solution by an agar plate culture method (37 ° C., 24 hours) using a standard agar medium for measuring the number of bacteria (manufactured by Nissui Co., Ltd.). Convert.

The test results are expressed as the logarithmic value of the difference in the number of viable bacteria from the blank. Since it is a logarithmic value, a difference of 1 means that a single digit value is different, that is, there is a difference of 10 times effect. That is, the larger the value, the greater the effect. In addition, Escherichia coli (IFO3301) was used as a test bacterium. The test bacterial solution is prepared by suspending Escherichia coli in a solution prepared by dissolving 5 mg of meat extract, 10 mg of peptone, and 5 mg of sodium chloride in 1 liter of distilled water, and adjusting the number of bacteria per ml to about 10 ⁶ .

<Melt flow rate> ISO R113
Measured under the conditions of 5 kg load and 200 ° C. according to 3, and the measured value is expressed in g / 10 min. It is used as an index of moldability. <Vicat softening point> Measured according to ISO 306. This is used as an index of heat resistance.

<Appearance of Molded Article> Visually, there is no defect, and a defect-free product is represented by ○, and a defective product is represented by ×. <Raw materials> Stylon 40R manufactured by Asahi Kasei Kogyo Co., Ltd. as rubber-reinforced polystyrene (HIPS), Styron 6 manufactured by Asahi Kasei Kogyo Co., Ltd. as polystyrene (GPPS)
80, Styrac-ABS200 manufactured by Asahi Kasei Kogyo Co., Ltd. is used as an acrylonitrile-butadiene-styrene copolymer (ABS resin).

As the modified polyphenylene ether, one obtained by kneading polyphenylene ether and rubber-reinforced polystyrene at a ratio of 3: 7 using a twin-screw extruder is used. Tenac-C5520 manufactured by Asahi Kasei Kogyo Co., Ltd. is used as the polyacetal resin (POM), Show Allomer MK211 manufactured by Showa Denko KK is used as the polypropylene (PP), and Suntech-HD J310 manufactured by Asahi Kasei Kogyo Co., Ltd. is used as the high density polyethylene (HDPE).

As lignin compounds, Lignine (80%) manufactured by Tokyo Kasei Kogyo Co., Ltd., Dealalin
e (lignin 1), ligni manufactured by Tokyo Chemical Industry Co., Ltd.
ne (80%), alkaline (lignin 2) and Pearl Rex DP (lignin 3) manufactured by Nippon Paper Industries Co., Ltd. are used.

[0029]

Examples 1 to 11 and Comparative Examples 1 and 2 Each component was dry-blended at the ratios shown in Tables 1 and 2 and vented to a vacuum using a twin-screw extruder (with a PCM 45 mm vent manufactured by Ikegai Iron Works Co., Ltd.). Melt, knead, and pelletize while pulling. After drying the obtained pellet, a flat plate (100 mm × 100 mm × 2 mm (t)) for antibacterial evaluation and a sample piece for physical property test are formed by an injection molding machine (Autoshot 50C; manufactured by FANUC CORPORATION).

The evaluation results are shown in Tables 1 and 2.

[0031]

[Table 1]

[0032]

[Table 2]

As can be seen from Examples 1, 2, 3 and Comparative Example 1, the resin composition of the present invention is excellent in moldability without lowering the Vicat softening point which is an index of heat resistance. Furthermore, antibacterial properties are also exhibited.

[0034]

Industrial Applicability The resin composition of the present invention exhibits excellent antibacterial properties and has excellent moldability without deteriorating heat resistance.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI (C08L 25/04 97:00)

Claims (3)

[Claims] 1. A resin composition comprising 99.9 to 70% by weight of a thermoplastic resin and 0.1 to 30% by weight of a lignin compound. 2. The resin composition according to claim 1, wherein the thermoplastic resin is a styrene resin. 3. An antibacterial resin composition comprising the resin composition according to claim 1.