JP6864522B2 - pellet - Google Patents

Description

The present invention relates to pellets containing parabens.

In recent years, the number of processed products made of functional resins has increased, and in particular, antibacterial processed products made of resins having antibacterial functions are widely used in ordinary households. As a means for adding an antibacterial function to the resin, a method of applying a paint containing an antibacterial agent to the resin surface, a method of mixing an antibacterial agent in the resin, and the like are known.

As antibacterial agents used for such applications, inorganic antibacterial agents such as silver-based antibacterial agents and zinc-based antibacterial agents having high antibacterial function and high safety are used (Patent Documents 1 and 2).

However, when an inorganic antibacterial agent is mixed with the resin, the antibacterial agent is an inorganic solid, so that the dispersibility is inferior in the thermoplastic organic resin. Therefore, as a conventional method of kneading into a resin, an antibacterial agent is once mixed in the same resin as the resin of the product material at a high concentration to form an antibacterial masterbatch formed into granules, and the resin material at the time of product molding is formed. A method of mixing a predetermined amount of the antibacterial masterbatch therein has been proposed. However, even when the antibacterial masterbatch is used, the dispersibility of the inorganic antibacterial agent is not always sufficient, and the inorganic antibacterial agent is discolored or clouded by light, or the physical properties of the resin itself are deteriorated. There was a problem such as.

On the other hand, many organic antibacterial agents have higher compatibility with various resins than inorganic antibacterial agents, and have advantages such as easy kneading with resins and uniform dispersion. For example, naturally derived antibacterial agents. A method of incorporating an antibacterial agent into a resin has been proposed (Patent Document 3). However, organic antibacterial agents generally have high volatility, and there are problems that it is difficult to melt and knead with a resin, and that the antibacterial property is remarkably lowered when mixed with a resin. In addition, many of them have not been sufficiently confirmed to be safe for the human body, which could be a cause of problems such as allergies. Therefore, the number of products using an organic antibacterial agent in the resin was smaller than that of products using an inorganic antibacterial agent in the resin.

JP-A-2005-047884 JP 2015-105252 JP 2013-237653

An object of the present invention is to provide pellets having excellent functionality such as safety and antibacterial properties and in which functional agents are uniformly dispersed.

As a result of diligent studies on functional pellets, the present inventors have observed that particles of parabens (parahydroxybenzoic acid esters) having a particle size of 5 μm or less are dispersed in a thermoplastic resin to improve safety and antibacterial properties. We have found that pellets having excellent functionality and uniformly dispersed functional agents can be obtained, and have completed the present invention.

（Ｒ_１は水素原子またはアルカリ金属、Ｒ_２は炭素原子数１〜１０のアルキル基またはアリール基を示す。） That is, the present invention contains a thermoplastic resin and a compound represented by the formula (1), and the compound represented by the formula (1) as a functional agent is dispersed in the thermoplastic resin as particles having a particle size of 5 μm or less. Provide pellets.

(R ₁ represents a hydrogen atom or an alkali metal, and R ₂ represents an alkyl group or an aryl group having 1 to 10 carbon atoms.)

Since the pellet of the present invention (hereinafter, also referred to as antibacterial pellet) is excellent in functionality such as safety and antibacterial property, it can also be used in a product that comes into contact with the human body. Further, since the functional agent is uniformly dispersed in the pellet of the present invention, the molded product, hollow molded product, film, sheet, textile product, etc. made of the pellet of the present invention have less bias in functionality depending on the part of the product. ..

6 is a scanning electron micrograph of the surface of the resin molded product obtained in Example 1. 6 is a scanning electron micrograph of the surface of the resin molded product obtained in Example 5. 3 is a scanning electron micrograph of the surface of the resin molded product obtained in Comparative Example 3.

Examples of the thermoplastic resin used in the present invention include polypropylene, polyethylene, polyoxymethylene, polyamide, polycarbonate, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), and acrylonitrile-styrene copolymer resin (AS resin). , One or more resins selected from the group consisting of polyesters and thermoplastic elastomers or copolymer resins thereof. Among them, polypropylene or polyethylene is excellent in compatibility with the compound represented by the formula (1). preferable.

In the compound represented by the formula (1), R ₁ is preferably a hydrogen atom, sodium or potassium, and more preferably a hydrogen atom.

In the compound represented by the formula (1), R ₂ is preferably an alkyl group or an aryl group having 1 to 6 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group or a group. It is a benzyl group, more preferably a butyl group or a hexyl group.

Specific examples of the compound represented by the formula (1) used in the present invention include methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, 4-. One or more selected from the group consisting of hexyl hydroxybenzoate and benzyl 4-hydroxybenzoate can be mentioned, and butyl 4-hydroxybenzoate and hexyl 4-hydroxybenzoate are highly antibacterial and difficult to sublimate. Is preferable.

The method for obtaining the compound represented by the formula (1) is not particularly limited, but a commercially available compound may be used, or 4-hydroxybenzoic acid and an aliphatic alcohol having 1 to 10 carbon atoms may be used in the presence of a catalyst. Those obtained by reaction with an aryl alcohol may be used.

The pellet of the present invention preferably contains 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass of the compound represented by the formula (1) with respect to 100 parts by mass of the thermoplastic resin. It is more preferably contained in an amount of 3 to 15 parts by mass, and particularly preferably contained in an amount of 5 to 15 parts by mass. Further, if the content of the compound represented by the formula (1) is less than 0.5 parts by mass with respect to 100 parts by mass of the thermoplastic resin, functionality such as antibacterial property is not exhibited, and the pellet masterbatch. If it exceeds 30 parts by mass, the physical properties of the resin may be problematic, and the compound represented by the formula (1) may precipitate or aggregate in the pellets.

In addition to the antibacterial function, the pellet of the present invention has an antifungal, algae-proof and insect-proof function against mites and the like.

The pellet of the present invention may contain an additive in addition to the thermoplastic resin and the compound represented by the formula (1), and the additive includes a colorant, a flame retardant, a heat stabilizer, a plasticizer, and the like. Selected from the group consisting of various additives such as light stabilizers (ultraviolet absorbers, etc.), antistatic agents, dispersants, mold release agents, reinforcing agents such as fibrous reinforcing agents, and fillers such as powder bulking agents. One or more can be mentioned. However, it is more effective not to support an inorganic substance that serves as a carrier of the compound or an organic substance that does not melt during pelletization in terms of uniform dispersibility due to micronization of the compound.

The shape of the pellet of the present invention is not particularly limited, and may be, for example, a prismatic shape, a spherical shape, a columnar shape, or the like. As for the size of the pellet, the maximum side length is preferably 1 to 20 mm in the case of a prismatic shape, the particle size is preferably 1 to 20 mm in the case of a spherical shape, and the diameter is preferably 1 to 20 mm in the case of a columnar shape. It is preferably 1.5 to 5 mm and the height is preferably 1.5 to 5 mm. When the size of the pellets is within the above range, the handleability is improved and the pellet packaging work and the like are facilitated. Further, the pellet can also be used as a powder composed of fine particles having a particle size of 0.1 to 1 mm. The powder can be obtained by using a known fine grinder for pellets.

The method for producing pellets of the present invention is not particularly limited, but for example, a resin composition containing a compound represented by the formula (1) and a thermoplastic resin (hereinafter, also referred to as resin composition 1) is extruded. A method can be used in which the sheet-shaped molded product is formed into a sheet by molding, and the obtained sheet-shaped molded product is cut into an appropriate size by a cutter or the like and processed into pellets.

The resin composition 1 constituting the pellet of the present invention can be produced by mixing a thermoplastic resin and a compound represented by the formula (1). The mixing may be carried out by melting and mixing the thermoplastic resin and the compound represented by the formula (1), or the resin obtained by heating and melting the compound represented by the formula (1) in a solvent. It may be carried out by mixing with and removing the solvent from the molten resin in a gaseous state.

When the thermoplastic resin and the compound represented by the formula (1) are melt-mixed, they are uniformly mixed in advance with a mixer such as a tumbler blender, a Henschel mixer or a super mixer, and then a single-screw extruder or a multi-screw extruder. Examples thereof include a method of melt-kneading with a cutter and cutting the extruded strands with a cutter or the like to granulate, and a method of melt-kneading with a kneader or a Banbury mixer and then granulating with an extruder.

The heating conditions differ depending on the thermoplastic resin used, the compound represented by the formula (1), the type and blending amount of the additive, the conditions of the mixer used, and the like, and therefore cannot be unconditionally specified, but the thermoplastic used. It is desirable to heat for 1 to 600 seconds at a temperature equal to or higher than the crystal melting temperature of the resin and lower than the deterioration temperature of the thermoplastic resin and the compound.

When the compound represented by the formula (1) is dissolved in a solvent and mixed with the resin melted by heating, the solvent is particularly limited as long as it dissolves the compound represented by the formula (1). Not, but organic solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, toluene, xylene, mesitylene, diethyl ether, tetrahydrofuran, dioxane, diphenyl ether, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone. , Dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride and the like.

The temperature at which the compound represented by the formula (1) is dissolved in the solvent is not particularly limited, but may be, for example, 10 to 80 ° C. Further, the compound represented by the formula (1) can be dissolved in 100 parts by mass of the solvent in an amount in the range of, for example, 10 to 200 parts by mass.

The mixed compound represented by the formula (1) is in a state of being dispersed as particles having a particle size of 5 μm or less in the thermoplastic resin, that is, a state in which there are no particles having a particle size of more than 5 μm. If the particle size of the compound represented by the formula (1) in the thermoplastic resin exceeds 5 μm, it tends to be difficult to obtain functionality such as sufficient antibacterial properties. The compound represented by the formula (1) in the thermoplastic resin is preferably dispersed as particles having a particle size of 2.5 μm or less, and more preferably dispersed as particles having a particle size of 1 μm or less in the thermoplastic resin. A state, more preferably a state in which the particles are dispersed as particles having a particle size of 0.1 μm or less. The state of the particles can be confirmed by observing with a scanning electron microscope (SEM). The particle size was measured by an image analysis method that measures the distance between two points, which is the maximum dimension for one particle, in a scanning electron microscope image. The particle size of the compound represented by the formula (1) in the pellet tends to be difficult to change even through the manufacturing process of a molded product or the like. Therefore, the particle size of the compound represented by the formula (1) in the pellet and the particle size of the compound represented by the formula (1) in the molded product or the like produced by using the pellet are substantially the same.

Since the pellet represented by the formula (1) is uniformly dispersed in the pellet of the present invention, it uniformly has functions such as antibacterial properties of the compound. It is suitably used as a material for textile products and the like. The antibacterial activity value in the present invention was measured in accordance with JIS Z 2801: 2010.

The pellet of the present invention can be molded into a molded product, a hollow molded product, a film, a sheet, a textile product, etc. by using it as it is without mixing it with the base resin or by mixing it with the base resin and using it as a masterbatch. can do. The pellet of the present invention is preferably used as a masterbatch. In the present invention, the masterbatch refers to pellets containing the compound represented by the formula (1) at a high concentration of 1 part by mass or more with respect to 100 parts by mass of the thermoplastic resin, and is represented by the formula (1). It is mixed with a base resin that does not contain the compound to be molded, and molded together with the base resin. When the masterbatch is used, the handleability of the material is easy and the weighing accuracy is improved as compared with the case where the compound represented by the formula (1) is directly added to the base resin for molding. Further, when the masterbatch is used, there is an advantage that a molded product containing fine particles of the compound represented by the formula (1) can be produced by using a general-purpose molding machine.

Examples of the base resin include those described above as the thermoplastic resin used for pellets (that is, masterbatch). The base resin may be the same as or different from the thermoplastic resin contained in the masterbatch, and a resin having high compatibility with the thermoplastic resin contained in the masterbatch is particularly preferable.

The amount of the masterbatch blended into the base resin can be appropriately changed depending on the compound represented by the formula (1) in the masterbatch and the amount thereof, and the masterbatch is diluted with the resin, for example, 2 to 40 times. It is desirable to mix them. If the amount of masterbatch is smaller than the above range, sufficient antibacterial performance cannot be imparted to the molded product, while if the amount of masterbatch is larger than the above range, the moldability may be inferior.

（Ｒ _１ は水素原子またはアルカリ金属、Ｒ _２ は炭素原子数１〜１０のアルキル基またはアリール基を示す。）
〔２〕熱可塑性樹脂がポリプロピレン、ポリエチレン、ポリオキシメチレン、ポリアミド、ポリカーボネート、ポリ塩化ビニル、アクリロニトリル−ブタジエン−スチレン共重合樹脂、アクリロニトリル−スチレン共重合樹脂、ポリエステルおよび熱可塑性エラストマーからなる群から選択される１種以上である、〔１〕に記載のペレット。
〔３〕熱可塑性樹脂がポリプロピレンまたはポリエチレンである、〔１〕または〔２〕に記載のペレット。
〔４〕式（１）で表される化合物が４−ヒドロキシ安息香酸メチル、４−ヒドロキシ安息香酸エチル、４−ヒドロキシ安息香酸プロピル、４−ヒドロキシ安息香酸ブチル、４−ヒドロキシ安息香酸ヘキシルおよび４−ヒドロキシ安息香酸ベンジルからなる群から選択される１種以上である、〔１〕〜〔３〕のいずれかに記載のペレット。
〔５〕式（１）で表される化合物が４−ヒドロキシ安息香酸ブチルまたは４−ヒドロキシ安息香酸ヘキシルである、〔１〕〜〔４〕のいずれかに記載のペレット。
〔６〕熱可塑性樹脂１００質量部に対して式（１）で表される化合物を０．５〜３０質量部含有する、〔１〕〜〔５〕のいずれかに記載のペレット。
〔７〕〔１〕〜〔６〕のいずれかに記載のペレットから構成される成形品、中空成形体、フィルム、シートまたは繊維製品。
〔８〕〔１〕〜〔６〕のいずれかに記載のペレットのマスターバッチとしての使用。 A resin composition (hereinafter, also referred to as resin composition 2) or pellet obtained by blending a master batch with a base resin is subjected to conventionally known melt molding such as double roll method, injection molding, extrusion molding, and compression molding. This makes it possible to obtain an antibacterial molded product having a shape suitable for the intended use of the final molded product, for example, a molded product, a hollow molded product, a film, a sheet, a textile product, or the like. That is, the molded article, hollow molded article, film, sheet and textile product of the present invention may be directly composed of pellets, or may be composed of pellets as a masterbatch and a base resin. May be good.
Preferred embodiments of the present invention include:
[1] A pellet containing a thermoplastic resin and a compound represented by the formula (1), in which the compound is dispersed as particles having a particle size of 5 μm or less in the thermoplastic resin.
[Chemical 1]

(R ₁ represents a hydrogen atom or an alkali metal, and R ₂ represents an alkyl group or an aryl group having 1 to 10 carbon atoms.)
[2] The thermoplastic resin is selected from the group consisting of polypropylene, polyethylene, polyoxymethylene, polyamide, polycarbonate, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, polyester and thermoplastic elastomer. The pellet according to [1], which is one or more of the following types.
[3] The pellet according to [1] or [2], wherein the thermoplastic resin is polypropylene or polyethylene.
[4] The compounds represented by the formula (1) are methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, hexyl 4-hydroxybenzoate and 4-hydroxybenzoate. The pellet according to any one of [1] to [3], which is one or more selected from the group consisting of benzyl hydroxybenzoate.
[5] The pellet according to any one of [1] to [4], wherein the compound represented by the formula (1) is butyl 4-hydroxybenzoate or hexyl 4-hydroxybenzoate.
[6] The pellet according to any one of [1] to [5], which contains 0.5 to 30 parts by mass of the compound represented by the formula (1) with respect to 100 parts by mass of the thermoplastic resin.
[7] A molded article, hollow molded article, film, sheet or textile product composed of the pellets according to any one of [1] to [6].
[8] Use of the pellet according to any one of [1] to [6] as a masterbatch.

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

The antibacterial agents A to D used in Examples and Comparative Examples, and each measuring method are shown below.
≪Antibacterial agent A≫
4-Hydroxybenzoic acid butyl ester (obtained by reacting 4-hydroxybenzoic acid with butyl alcohol in the presence of a catalyst)
≪Antibacterial agent B≫
4-Hydroxybenzoic acid hexyl ester (obtained by reacting 4-hydroxybenzoic acid with hexyl alcohol in the presence of a catalyst)
≪Antibacterial agent C≫
Zeolite silver (manufactured by Fuji Chemical Co., Ltd., product name: Bacterite, product number: MP-102SVC13)
≪Antibacterial agent D≫
Silver behenate (manufactured by Tokyo Chemical Industry Co., Ltd.)

(Measuring method)
(1) Antibacterial test Test method: JIS Z 2801: 2010
Test strain: Escherichia coli NBRC 3972
Test strain: Staphylococcus aureus NBRC 12732

A bacterial solution containing Escherichia coli and Staphylococcus aureus was dropped onto the surface of the resin molded product containing the antibacterial agent obtained in Examples and Comparative Examples, and a polyethylene film was adhered thereto, and the temperature was 35 ° C. and the humidity was 90%. Was cultured for 24 hours under the conditions of. After culturing, take 1 mL of the solution (VmL) obtained by washing out the cells adhering to the polyethylene film and the test piece with SCDLP medium, transfer 1 mL of the diluted (D-fold diluted) solution to a petri dish, and transfer about 20 mL of SPC medium. Was added and mixed. After the medium had solidified, the cells were cultured for 40 to 48 hours under the conditions of a temperature of 35 ° C. and a humidity of 90%, and then the viable numbers of Escherichia coli and Staphylococcus aureus were counted. As the evaluation standard, a polypropylene resin molded product containing no pellets (hereinafter, also referred to as an unprocessed resin molded product) was used. Each test was performed 3 times and the average value was calculated.

The evaluation of the antibacterial test was calculated by the following method.
N = (C × D × V) / A
N: Viable cell count (per ^{1 cm 2 test piece)}
C: Number of settlements (average number of settlements of the two petri dishes adopted)
D: Dilution factor (dilution factor of the diluted solution dispensed into the adopted petri dish)
V: Liquid volume (mL) of SCDLP medium used for washing out
A: Surface area of coating film (cm ² )
However, when C is <1, the viable cell count is calculated with C as 1.
For example, when V = 10 mL, A = 16 cm ² , and D = 1, it is displayed as N <0.63.
_{R = (U t -U 0)} - (A t -U 0) = U t -A t
R: antibacterial activity value U _0: No machining mean value of number of living bacteria logarithmic value immediately after inoculation of the resin molded body U _t: mean A _t logarithm of the number of viable bacteria after 24 hours of non-processed resin molding : Average value of logarithmic number of viable cells after 24 hours of resin molded product containing antibacterial agent obtained in Examples and Comparative Examples Antibacterial activity evaluation: Antibacterial activity value R of 3.0 or more ⊚, 2.0 More than 3.0 was evaluated as ◯, 1.5 or more and less than 2.0 was evaluated as Δ, and more than 1.5 was evaluated as ×.

(2) Observation of antibacterial agent particles The surface of the resin molded body was observed using a scanning electron microscope (SEM) at an appropriate magnification. Judgment was made according to the following criteria.
◯: No particles having a particle size exceeding 1 μm were observed.
Δ: Particles having a particle size of more than 1 μm and less than 5 μm were observed.
X: Particles having a particle size of more than 5 μm were observed.

(3) Evaluation of colorability The resin molded body was measured using a spectrophotometer (type CM-3600d (manufactured by KONICA MINOLTA), color software CM-S100W Spectra Magic NX, measurement method: reflection, field of view: 10 °, main light source: B * was measured under the conditions of C light source, dimeotri: d / 8, normal reflected light treatment: SCI + SCE, measurement diameter: LAV (25.4 mm), and UV condition: 100%, and the determination was made according to the following criteria.
⊚: b * is less than 2 ○: b * is 2 or more and less than 20 Δ: b * is 20 or more and less than 40 ×: b * is 40 or more

[Example 1]
(Preparation of antibacterial pellets)
100 g of the antibacterial agent A was dissolved in 150 g of methanol at 50 ° C. Antibacterial agent A dissolved in methanol was melted at a temperature of 200 ° C. so that 11 parts by mass of antibacterial agent A was blended with 100 parts by mass of polypropylene resin (Prime Polymer Co., Ltd., J105G). The polypropylene resin was supplied to a twin-screw extruder (manufactured by Ikekai Co., Ltd., PCM-30), melt-kneaded, and pelletized by removing methanol in a gaseous state to obtain antibacterial pellets.

(Preparation of resin molded product)
The obtained antibacterial pellets and polypropylene resin (manufactured by Prime Polymer Co., Ltd., J105G) are mixed at the ratios shown in Table 1 and injected using an injection molding machine (UH-1000-110 manufactured by Nissei Resin Industry Co., Ltd.). Molding was performed to obtain a resin molded product. When the surface of the obtained resin molded product was observed with a scanning electron microscope (SEM) at a magnification of 10000 times, no particles were observed. A scanning electron micrograph is shown in FIG. In addition, the obtained resin molded product was subjected to an antibacterial property test and an evaluation of colorability. The results are shown in Table 1.

[Examples 2 to 4]
Antibacterial pellets and resin molded products were obtained in the same manner as in Example 1 except that the mixing ratio of the antibacterial pellets of the resin molded product and the polypropylene resin was changed as shown in Table 1. Each of the obtained resin molded products was subjected to an antibacterial property test, surface observation with a scanning electron microscope, and evaluation of colorability. The results are shown in Table 1.

[Examples 5 to 8]
Antibacterial pellets and resin molded products were obtained in the same manner as in Example 1 except that the type of antibacterial agent and the mixing ratio of the antibacterial pellets of the resin molded product and the polypropylene resin were changed as shown in Table 1. When the surface of each of the obtained resin molded products was observed with a scanning electron microscope (SEM) at a magnification of 10000 times, no particles were observed. A scanning electron micrograph of Example 5 is shown in FIG. In addition, each of the obtained resin molded products was subjected to an antibacterial property test and an evaluation of colorability. The results are shown in Table 1.
[Examples 9 to 10]

(Preparation of antibacterial pellets)
Antibacterial pellets were obtained in the same manner as in Example 1 except that the ratio of the antibacterial agent A was changed as shown in Table 1.

(Preparation of resin molded product)
A resin molded product was obtained in the same manner as in Example 1 except that the ratio of the obtained antibacterial pellets was changed as shown in Table 1. When the surface of each of the obtained resin molded products was observed with a scanning electron microscope (SEM) at a magnification of 10000 times, no particles were observed. In addition, each of the obtained resin molded products was subjected to an antibacterial property test and an evaluation of colorability. The results are shown in Table 1.

[Example 11] (Reference example)
(Preparation of antibacterial pellets)
Antibacterial pellets were obtained in the same manner as in Example 1 except that the ratio of the antibacterial agent A was changed as shown in Table 1.

(Preparation of resin molded product)
The obtained antibacterial pellets were injection-molded using an injection molding machine (UH-1000-110 manufactured by Nissei Resin Industry Co., Ltd.) to obtain a resin molded product. When the surface of each of the obtained resin molded products was observed with a scanning electron microscope (SEM) at a magnification of 10000 times, no particles were observed. In addition, the obtained resin molded product was subjected to an antibacterial property test and an evaluation of colorability. The results are shown in Table 1.

[Comparative Examples 1-2]
The polypropylene resin and each antibacterial agent were supplied to a twin-screw extruder (manufactured by Ikekai Co., Ltd., PCM-30) in proportions and the antibacterial agents shown in Table 1, and melt-kneaded to obtain antibacterial pellets. Using the obtained antibacterial pellets, a resin molded product was obtained in the same manner as in Example 1. When the surface of each of the obtained resin compositions was observed at a magnification of 3000 times using a scanning electron microscope (SEM), particles having a particle size of more than 5 μm were observed. In addition, each of the obtained resin molded products was subjected to an antibacterial property test and an evaluation of colorability. The results are shown in Table 1.

[Comparative Example 3]
(Preparation of resin molded product)
The antibacterial agent (A) and polypropylene resin (manufactured by Prime Polymer Co., Ltd., J105G) are mixed at the ratios shown in Table 1 and injected using an injection molding machine (UH-1000-110 manufactured by Nissei Resin Industry Co., Ltd.). Molding was performed to obtain a resin molded product. When the surface of the obtained resin molded body was observed with a scanning electron microscope (SEM) at a magnification of 3000 times, particles having a particle size of more than 5 μm were observed. A scanning electron micrograph is shown in FIG. In addition, the obtained resin molded product was subjected to an antibacterial property test and an evaluation of colorability. The results are shown in Table 1.

Claims (7)

Pellets containing 5 to 30 parts by mass of the compound represented by the formula (1) with respect to 100 parts by mass of the thermoplastic resin and the thermoplastic resin, and the compound dispersed as particles having a particle diameter of 1 μm or less in the thermoplastic resin. ..

(R ₁ represents a hydrogen atom or an alkali metal, and R ₂ represents an alkyl group or an aryl group having 1 to 10 carbon atoms.) One type of thermoplastic resin selected from the group consisting of polypropylene, polyethylene, polyoxymethylene, polyamide, polycarbonate, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene copolymer resin, polyester and thermoplastic elastomer. The pellet according to claim 1, which is the above. The pellet according to claim 1 or 2, wherein the thermoplastic resin is polypropylene or polyethylene. The compounds represented by the formula (1) are methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, hexyl 4-hydroxybenzoate and 4-hydroxybenzoate. The pellet according to any one of claims 1 to 3, which is one or more selected from the group consisting of benzyl. The pellet according to any one of claims 1 to 4, wherein the compound represented by the formula (1) is butyl 4-hydroxybenzoate or hexyl 4-hydroxybenzoate. A molded product, hollow molded product, film, sheet or textile product composed of the pellets according to any one of claims 1 to 5. Use of the pellet according to any one of claims 1 to 5 as a masterbatch.

Images