JP2018172347A - pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pellet that has excellent functionalities such as safety and antibacterial properties, and includes a functional agent uniformly dispersed therein.SOLUTION: A pellet comprises a thermoplastic resin and a compound represented by formula (1), where the compound represented by formula (1) is dispersed in the thermoplastic resin with a particle size of 5 μm or less (Ris a hydrogen atom or an alkali metal, Ris a C1 to 10 alkyl group or an aryl group).SELECTED DRAWING: None

Description

  The present invention relates to pellets containing parabens.

  In recent years, processed products made of a resin having functionality have increased, and in particular, antibacterial processed products made of a resin having an antibacterial function are widely used in general households. As 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 antibacterial agents and zinc antibacterial agents having a high antibacterial function and high safety are used (Patent Documents 1 and 2).

  However, when an inorganic antibacterial agent is mixed in the resin, the antibacterial agent is an inorganic solid, and therefore dispersibility is poor in a thermoplastic organic resin. Therefore, as a conventional kneading method into the resin, the antibacterial masterbatch formed into a granular form once mixed with the antibacterial agent at a high concentration in the same resin as the resin of the product material, the resin material at the time of product molding A method of mixing a predetermined amount of the antibacterial masterbatch therein has been proposed. However, even when an antibacterial masterbatch is used, it cannot be said that the dispersibility of the inorganic antibacterial agent is sufficient, and the inorganic antibacterial agent is discolored or clouded by light, or the physical properties of the resin itself are reduced. 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 the advantage of being easy to knead and uniformly disperse with resins. 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 it has been difficult to melt and knead them with a resin, or when mixed with a resin, the antibacterial properties are significantly reduced. In addition, there are many cases where safety to the human body has not been sufficiently confirmed, and it could be a cause of problems such as allergies. Therefore, there were few products using organic antibacterial agents in the resin compared to products using inorganic antibacterial agents in the resin.

JP 2005-047884 A JP2015-105252A JP2013-237653A

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

  As a result of intensive studies on the functional pellets, the present inventors have dispersed particles of parabens (parahydroxybenzoic acid esters) having a particle size of 5 μm or less in a thermoplastic resin, thereby improving safety and antibacterial properties. It has been found that pellets with excellent functionality and a functional agent uniformly dispersed can be obtained, and the present invention has been completed.

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 as particles having a particle diameter of 5 μm or less in the thermoplastic resin. 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 pellets of the present invention (hereinafter sometimes referred to as antibacterial pellets) are excellent in safety and antibacterial functionality, they can also be used for products that come into contact with the human body. Further, since the functional agent is uniformly dispersed in the pellet of the present invention, the molded product, the hollow molded body, the film, the sheet, the fiber product, and the like made of the pellet of the present invention are less functionally uneven depending on the product part. .

2 is a scanning electron micrograph of the surface of a resin molded body obtained in Example 1. FIG. 6 is a scanning electron micrograph of the surface of a resin molded body obtained in Example 5. FIG. 4 is a scanning electron micrograph of the surface of a resin molded body 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 polyester and thermoplastic elastomer or copolymer resins thereof are mentioned. Among them, polypropylene or polyethylene is used because of excellent 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, more preferably a hydrogen atom.

In the compound represented by the formula (1), R ₂ is preferably an alkyl group having 1 to 6 carbon atoms or an aryl group, more preferably a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group or 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- 1 or more types selected from the group consisting of hexyl hydroxybenzoate and benzyl 4-hydroxybenzoate are mentioned, butyl 4-hydroxybenzoate and hexyl 4-hydroxybenzoate are highly antibacterial and non-sublimable. Is preferred.

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

  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 preferable to contain 3-15 mass parts, and it is especially preferable to contain 5-15 mass parts. In addition, when 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, functions such as antibacterial properties are not exhibited, and a master batch of pellets When it exceeds 30 parts by mass, there is a problem in physical properties as a resin, and the compound represented by the formula (1) may be precipitated or aggregated in the pellet.

  The pellet of the present invention has an antibacterial function, an antifungal function, an algae control, an insect control 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). Examples of the additive include a colorant, a flame retardant, a heat stabilizer, a plasticizer, Selected from the group consisting of light stabilizers (such as ultraviolet absorbers), various additives such as antistatic agents, dispersants, mold release agents, reinforcing agents such as fibrous reinforcing agents, and fillers such as powder extenders. One or more. However, it is more effective not to support an inorganic substance that becomes a carrier of the compound or an organic substance that does not melt during pelletization in terms of uniform dispersibility by compounding 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 cylindrical shape, or the like. As for the size of the pellet, the length of the maximum side is preferably 1 to 20 mm in the case of a prismatic shape, the particle diameter is preferably 1 to 20 mm in the case of a spherical shape, and the diameter in the case of a columnar shape. It is preferable that the height is 1.5 to 5 mm and the height is 1.5 to 5 mm. When the size of the pellet is within the above range, the handleability is improved, and the pellet packaging operation and the like are facilitated. Moreover, the said pellet can also be used as powder which consists of microparticles | fine-particles whose particle diameter is 0.1-1 mm. The powder can be obtained by using a known pulverizer.

  Although it does not specifically limit as a manufacturing method of the pellet of this invention, For example, the resin composition (henceforth the resin composition 1) containing the compound represented by Formula (1) and a thermoplastic resin is extruded. A method of forming into a sheet by molding, cutting the obtained sheet-like product into an appropriate size with a cutter or the like, and processing it into a pellet can be used.

  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 performed by melt-mixing the thermoplastic resin and the compound represented by formula (1), and the resin melted by heating in a state where the compound represented by formula (1) is dissolved in a solvent. And the solvent may be removed from the molten resin in a gaseous state.

  When the thermoplastic resin and the compound represented by the formula (1) are melt-mixed, for example, after being uniformly mixed in a mixer such as a tumbler blender, a Henschel mixer or a super mixer, a single-screw extruder or a multi-screw extruder is used. And a method of granulating the extruded strand by cutting with a cutter or the like, and a method of melting and kneading with a kneader or a Banbury mixer and then granulating with an extruder.

  The heating conditions differ depending on the thermoplastic resin to be used, the compound represented by the formula (1), the type and amount of additives, the conditions of the mixer to be used, and the like. 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.

  In the case where the compound represented by the formula (1) is dissolved in a solvent and mixed with the heat-melted resin, the solvent is particularly limited as long as it dissolves the compound represented by the formula (1). 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.

  Although it does not specifically limit as temperature which dissolves the compound represented by Formula (1) in a solvent, For example, you may be 10-80 degreeC. Moreover, the compound represented by Formula (1) can be dissolved in the quantity of the range of 10-200 mass parts with respect to 100 mass parts of solvents, for example.

  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, in a state where there are no particles having a particle size exceeding 5 μm. When 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 sufficient functionality such as 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 in the thermoplastic resin, more preferably as particles having a particle size of 1 μm or less. More preferably, the particle is dispersed as particles having a particle diameter of 0.1 μm or less. The state of the particles can be confirmed by observing with a scanning electron microscope (SEM). The particle diameter was measured by an image analysis method for measuring 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 hardly change even after a manufacturing process of a molded product or the like. Therefore, the particle diameter of the compound represented by the formula (1) in the pellet and the particle diameter of the compound represented by the formula (1) in a molded article or the like produced using the pellet are substantially the same.

  Since the compound represented by the formula (1) is uniformly dispersed in the pellets of the present invention, the pellets of the present invention are uniformly provided with functions such as antibacterial properties, so that the molded product, hollow molded body, film, sheet and It is suitably used as a material for textile products. In addition, the antibacterial activity value in this invention is measured based on JISZ2801: 2010.

  The pellets of the present invention can be molded into molded products, hollow molded products, films, sheets, textile products, etc. by using them as they are without mixing with the base resin, or by mixing them with the base resin and using them as master batches. can do. The pellet of the present invention is preferably used as a master batch. In the present invention, the master batch refers to a pellet 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). And mixed with a base resin that does not contain a compound to be molded together with the base resin. When the master batch is used, the handling property of the material is easy and the weighing accuracy is improved as compared with molding by directly adding the compound represented by the formula (1) to the base resin. Moreover, when a masterbatch is used, there also exists an advantage that the molded object containing the microparticles | fine-particles of the compound represented by Formula (1) can be manufactured using a general purpose molding machine.

  As an example of base resin, what was mentioned above as a thermoplastic resin used for a pellet (namely, masterbatch) is mentioned. The base resin may be the same as or different from the thermoplastic resin contained in the masterbatch, and is particularly preferably highly compatible with the thermoplastic resin contained in the masterbatch.

  The compounding amount of the masterbatch 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 to a resin, for example, 2 to 40 times. It is desirable to mix. When the amount of the master batch is smaller than the above range, sufficient antibacterial performance cannot be imparted to the molded body, while when the amount of the master batch is larger than the above range, the moldability may be inferior.

  A resin composition (hereinafter also referred to as “resin composition 2”) or a pellet obtained by blending a master batch with a base resin is subjected to conventionally known melt molding such as a two-roll method, injection molding, extrusion molding, and compression molding. Thereby, the shape according to the use of the final molded product, for example, an antibacterial molded product such as a molded product, a hollow molded product, a film, a sheet, and a textile product can be obtained. That is, the molded article, hollow molded article, film, sheet and fiber product of the present invention may be composed directly from pellets, and are composed of pellets as a master batch and a base resin. Also good.

  Hereinafter, although an example explains the present invention in detail, the present invention is not limited to this.

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

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

  The bacterial solution containing each of Escherichia coli and Staphylococcus aureus was dropped onto the surface of the resin molded body 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%. The cells were cultured for 24 hours under the above conditions. After culturing, 1 mL of the liquid (VmL) obtained by washing the bacterial cells adhering to the polyethylene film and the test piece with SCDLP medium is taken, and 1 mL of the diluted (D-fold diluted) liquid is transferred to a petri dish, and about 20 mL of SPC medium is obtained. And mixed. After the medium had solidified, the cells were cultured for 40 to 48 hours under conditions of a temperature of 35 ° C. and a humidity of 90%, and then the viable counts of Escherichia coli and Staphylococcus aureus were counted. As a criterion for evaluation, a polypropylene resin molded body containing no pellets (hereinafter also referred to as a non-processed resin molded body) was used. Each test was performed three times, and the average value was calculated.

The antibacterial test was calculated by the following method.
N = (C × D × V) / A
N: Number of viable bacteria (per 1 cm ² test piece)
C: Number of villages (average number of villages of the two petri dishes adopted)
D: Dilution factor (dilution ratio of the diluted solution dispensed to the adopted petri dish)
V: Volume of SCDLP medium used for washing out (mL)
A: Surface area of the coated film (cm ² )
However, when C is <1, C is set to 1 and the viable cell count is calculated.
For example, when V = 10 mL, A = 16 cm ² , and D = 1, N <0.63 is displayed.
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 value of the number of viable bacteria after 24 hours of the resin moldings containing antibacterial agents obtained in Examples and Comparative Examples Antibacterial activity evaluation: Antibacterial activity value R of 3.0 or more More than 3.0 and less than 3.0 were evaluated as ◯, 1.5 and less than 2.0 as Δ, and less than 1.5 as ×.

(2) Observation of antibacterial agent particles The surface of the resin molding was observed using a scanning electron microscope (SEM) with the magnification set appropriately. Judgment was made according to the following criteria.
○: Particles having a particle diameter exceeding 1 μm were not observed.
Δ: Particles having a particle diameter of more than 1 μm and not more than 5 μm were observed.
X: Particles having a particle diameter exceeding 5 μm were observed.

(3) Evaluation of colorability Using a spectrocolorimeter (model CM-3600d (manufactured by KONICA MINOLTA)) and color software CM-S100W Spectra Magic NX, the resin molding was measured using a measurement method: reflection, field of view: 10 °, main light source: B * was measured under the conditions of C light source, dimetrie: d / 8, regular reflection light treatment: SCI + SCE, measurement diameter: LAV (25.4 mm), 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 x: b * is 40 or more

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

(Production of resin molding)
The obtained antibacterial pellets and polypropylene resin (manufactured by Prime Polymer Co., Ltd., J105G) were mixed at the ratios shown in Table 1, and injected using an injection molding machine (Nissei Plastic Industries, Ltd. UH-1000-110). Molded to obtain a resin molded body. When the surface of the obtained resin molded body was observed at a magnification of 10,000 times using a scanning electron microscope (SEM), no particles were observed. A scanning electron micrograph is shown in FIG. In addition, the obtained resin molded body was subjected to an antibacterial test and coloring evaluation. The results are shown in Table 1.

[Examples 2 to 4]
An antibacterial pellet and a resin molded body were obtained in the same manner as in Example 1 except that the mixing ratio of the antibacterial pellet of the resin molded body and the polypropylene resin was changed as shown in Table 1. About each obtained resin molding, surface observation and coloring property evaluation were performed with the antibacterial test, the scanning electron microscope. The results are shown in Table 1.

[Examples 5 to 8]
An antibacterial pellet and a resin molded body were obtained in the same manner as in Example 1 except that the type of antibacterial agent and the mixing ratio of the antibacterial pellet of the resin molded body and the polypropylene resin were changed as shown in Table 1. When the surface of each obtained resin molding was observed at a magnification of 10,000 times using a scanning electron microscope (SEM), no particles were observed. A scanning electron micrograph of Example 5 is shown in FIG. Moreover, the antibacterial property test and coloring evaluation were performed about each obtained resin molding. The results are shown in Table 1.
[Examples 9 to 10]

(Production 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.

(Production of resin molding)
A resin molded body 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 obtained resin molding was observed at a magnification of 10,000 times using a scanning electron microscope (SEM), no particles were observed. Moreover, the antibacterial property test and coloring evaluation were performed about each obtained resin molding. The results are shown in Table 1.

[Example 11]
(Production 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.

(Production of resin molding)
The obtained antibacterial pellet was injection-molded using an injection molding machine (UH-1000-110 manufactured by Nissei Plastic Industry Co., Ltd.) to obtain a resin molded body. When the surface of each obtained resin molding was observed at a magnification of 10,000 times using a scanning electron microscope (SEM), no particles were observed. In addition, the obtained resin molded body was subjected to an antibacterial test and coloring evaluation. The results are shown in Table 1.

[Comparative Examples 1-2]
The antibacterial agent and each antibacterial agent shown in Table 1 were supplied to a twin screw extruder (Ikegai Co., Ltd., PCM-30) and melt kneaded to obtain antibacterial pellets. Using the obtained antibacterial pellets, a resin molded body was obtained in the same manner as in Example 1. When the surface of each obtained resin composition was observed by magnifying it 3000 times using a scanning electron microscope (SEM), particles having a particle diameter exceeding 5 μm were observed. Moreover, the antibacterial property test and coloring evaluation were performed about each obtained resin molding. The results are shown in Table 1.

[Comparative Example 3]
(Production of resin molding)
Antibacterial agent (A) and polypropylene resin (manufactured by Prime Polymer Co., Ltd., J105G) are mixed at the ratio shown in Table 1, and injected using an injection molding machine (Nissei Plastic Industries, Ltd. UH-1000-110). Molded to obtain a resin molded body. When the surface of the obtained resin molding was observed by magnifying it 3000 times using a scanning electron microscope (SEM), particles having a particle diameter exceeding 5 μm were observed. A scanning electron micrograph is shown in FIG. In addition, the obtained resin molded body was subjected to an antibacterial test and coloring evaluation. The results are shown in Table 1.

Claims (8)

A pellet containing a thermoplastic resin and a compound represented by formula (1), wherein the compound is dispersed as particles having a particle diameter of 5 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.)   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 claim 1, which is the above.   The pellet according to claim 1 or 2, wherein the thermoplastic resin is polypropylene or polyethylene.   The compound represented by formula (1) is methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, hexyl 4-hydroxybenzoate and 4-hydroxybenzoic acid. The pellet in any one of Claims 1-3 which is 1 or more types selected from the group which consists of benzyl.   The pellet in any one of Claims 1-4 whose compound represented by Formula (1) is 4-hydroxybenzoate butyl or 4-hydroxybenzoate hexyl.   The pellet in any one of Claims 1-5 which contains 0.5-30 mass parts of compounds represented by Formula (1) with respect to 100 mass parts of thermoplastic resins.   A molded article, a hollow molded article, a film, a sheet, or a textile product comprising the pellet according to any one of claims 1 to 6.   Use of the pellet according to any one of claims 1 to 6 as a master batch.