sealing member

Abstract

Provided is a sealing member that achieves a high level of balance between abrasion resistance and sealing properties.　This sealing member is constituted from a molded product of a resin composition, and is characterized in that the resin composition contains a thermoplastic elastomer (A) and a reinforcing material (B) having a Mohs' hardness of 5 or less, and in that, when the durometer hardness of the sealing member is measured in accordance with JIS K 6253-3：2012, the type A durometer hardness is more than 60 and less than 90.

Description

[Technical Field]

[0001] The present invention relates to a sealing member composed of a molded body of a resin composition. [Background technology]

[0002] Rubbers such as thermosetting elastomers are widely known as materials with excellent flexibility. However, since thermosetting elastomers require a thermosetting process, thermoplastic elastomers are widely known as materials that possess both rubber elasticity and flexibility, and can be melt-molded.

[0003] Thermoplastic elastomers are attracting attention as an energy-saving and resource-saving type of elastomer, due to their ability to streamline manufacturing processes as an alternative to vulcanized rubber, and because they are lightweight and easily recyclable. They are used in fields such as automotive parts, industrial machinery parts, electrical and electronic components, building materials, and medical equipment parts. In particular, composite materials consisting of thermoplastic elastomers and reinforcing fibers are used in belts, hoses, diaphragms, and vibration-damping rubbers because they possess both high rigidity and rubber elasticity. For example, Patent Document 1 below discloses a fiber-reinforced thermoplastic elastomer. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-201349 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, as described in Patent Document 1, when a thermoplastic elastomer reinforced with a reinforcing material is used in a sealing member involving sliding, it exhibits excellent wear resistance but lacks sufficient sealing performance. On the other hand, achieving excellent sealing performance requires reducing hardness, but this results in reduced wear resistance. Therefore, it is difficult to achieve both wear resistance and sealing performance in thermoplastic elastomers reinforced with reinforcing materials. This tendency was particularly pronounced when used in sealing members involving sliding contact with resin.

[0006] The present invention aims to solve these problems and provide a sealing member that can achieve a high level of both wear resistance and sealing performance. [Means for solving the problem]

[0007] The present invention provides a sealing member having the following configuration.

[0008] Item 1 A sealing member comprising a molded body of a resin composition, wherein the resin composition contains a thermoplastic elastomer (A) and a reinforcing material (B) having a Mohs hardness of 5 or less, and the type A durometer hardness of the sealing member is greater than 60 and less than 90 when measured in accordance with JIS K 6253-3:2012.

[0009] Item 2 The sealing member according to Item 1, characterized in that the reinforcing material (B) is a fibrous reinforcing material.

[0010] Item 3 The sealing member according to Item 2, characterized in that the average fiber length of the fibrous reinforcing material is 1 μm to 300 μm.

[0011] Item 4 The sealing member according to item 2 or 3, characterized in that the fibrous reinforcing material is an inorganic fiber.

[0012] Item 5. The sealing member according to any one of Items 2 to 4, characterized in that the fibrous reinforcing material is at least one of potassium titanate fiber and wollastonite fiber.

[0013] Item 6. The sealing member according to any one of Items 1 to 5, characterized in that the thermoplastic elastomer (A) is a polyester-based thermoplastic elastomer.

[0014] Item 7. The sealing member according to any one of Items 1 to 6, wherein in the resin composition, the content of the thermoplastic elastomer (A) is 60% by mass to 90% by mass, and the content of the reinforcing material (B) is 5% by mass to 35% by mass.

[0015] Item 8. The sealing member according to any one of Items 1 to 7, wherein the resin composition further contains a silicone resin (C).

[0016] Item 9. The sealing member according to Item 8, wherein in the resin composition, the content of the silicone resin (C) is 0.1% by mass to 8% by mass.

[0017] Item 10. The sealing member according to Item 8 or Item 9, wherein the content of fumed silica in the silicone resin (C) is 20% by mass or more and 40% by mass or less.

[0018] Item 11. The sealing member according to any one of Items 1 to 10, which is used in an application involving sliding with a resin.

[0019] Item 12. The sealing member according to any one of Items 1 to 11, which is a medical sealing member.

Advantages of the Invention

[0020] According to the present invention, it is possible to provide a sealing member capable of achieving high levels of both wear resistance and sealing performance.

Modes for Carrying Out the Invention

[0021] Preferred embodiments of the present invention will be described below. However, the following embodiments are merely illustrative, and the present invention is not limited to these embodiments.

[0022] The sealing member of the present invention is a sealing member composed of a molded body of a resin composition. The resin composition contains a thermoplastic elastomer (A) and a reinforcing material (B) having a Mohs hardness of 5 or less. When the durometer hardness of the sealing member is measured in accordance with JIS K 6253-3:2012, the Type A durometer hardness is greater than 60 and less than 90.

[0023] The sealing member of the present invention is made of a molded article of a resin composition containing a thermoplastic elastomer (A) and a reinforcing material (B) having a Mohs hardness of 5 or less. Since the Type A durometer hardness of the sealing member is within the specified range, it is possible to improve moldability while suppressing a decrease in the reinforcing effect of the reinforcing material (B), and to achieve a high level of both wear resistance and sealing performance. In particular, even when used in applications involving sliding with resin, it is possible to achieve a high level of both wear resistance (wear resistance between resins) and sealing performance.

[0024] The thermoplastic elastomer (A) is preferably a polyester-based thermoplastic elastomer. The reinforcing material (B) is preferably a fibrous reinforcing material. The average fiber length of the fibrous reinforcing material is preferably 1 μm to 300 μm. The fibrous reinforcing material is preferably an inorganic fiber, and more preferably at least one of potassium titanate fibers and wollastonite fibers. When such a thermoplastic elastomer (A) and reinforcing material (B) are used, the abrasion resistance and sealing performance of the sealing member can be achieved at an even higher level.

[0025] In the above resin composition, the content of thermoplastic elastomer (A) is preferably 60% to 90% by mass, and the content of reinforcing material (B) is preferably 5% to 35% by mass. In this case, the abrasion resistance and sealing performance of the sealing member can be achieved at an even higher level.

[0026] The above resin composition preferably further contains silicone resin (C). In the above resin composition, the content of silicone resin (C) is preferably 0.1% to 8% by mass. In this case, the wear resistance of the sealing member can be further improved.

[0027] Such sealing members of the present invention can be suitably used as medical sealing members.

[0028] The components of the sealing member of the present invention are described below.

[0029] <Resin composition> The resin composition used in the present invention contains a thermoplastic elastomer (A) and a reinforcing material (B) having a Mohs hardness of 5 or less, and may optionally contain a silicone resin (C) and other additives.

[0030] (Thermoplastic elastomer (A)) The thermoplastic elastomer (A) used in the present invention is an elastomer that has rubber-like elasticity at room temperature (20°C) and exhibits plasticity when heated. That is, it has both components in its molecule: an elastic rubber component (soft segment) and a molecular constraint component (hard segment) that prevents plastic deformation.

[0031] As the thermoplastic elastomer (A), depending on the type of soft and hard segments, for example, styrene-based thermoplastic elastomer (TPS), olefin-based thermoplastic elastomer (TPO), vinyl chloride-based thermoplastic elastomer (TPVC), urethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer (TPEE), etc., can be used.

[0032] From the viewpoint of further improving mechanical strength and abrasion resistance, the thermoplastic elastomer (A) is preferably a urethane-based thermoplastic elastomer (TPU), a polyester-based thermoplastic elastomer (TPEE), or a styrene-based thermoplastic elastomer (TPS), and more preferably a polyester-based thermoplastic elastomer (TPEE) or a urethane-based thermoplastic elastomer (TPU). A polyester-based thermoplastic elastomer (TPEE) is even more preferable because it has superior abrasion resistance and mechanical strength, as well as lower moisture absorption and superior moldability (molding accuracy).

[0033] Furthermore, since polyester thermoplastic elastomers (TPEE) exhibit excellent heat-sealability with thermoplastic resins (excluding thermoplastic elastomers) such as polycarbonate (PC) resin, polylactic acid (PLA) resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polycyclohexylene dimethylene terephthalate (PCT) resin, resin compositions containing polyester thermoplastic elastomers (TPEE) can be suitably used for integral molding with the above-mentioned thermoplastic resins (excluding thermoplastic elastomers).

[0034] In the present invention, the polyester-based thermoplastic elastomer (TPEE) more preferably used as thermoplastic elastomer (A) is a polyester-ether type block copolymer in which the hard segment is composed of aromatic polyester blocks (x) and the soft segment is composed of aliphatic polyether blocks (y), wherein the aliphatic polyether block (y) consists mainly of polyalkylene ether glycol. These polyester-based thermoplastic elastomers (TPEE) may be used individually or in combination of two or more types.

[0035] Examples of dicarboxylic acids or their ester-forming derivatives that constitute the aromatic polyester block (x) include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, 1,4- or 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, and 4,4'-diphenylsulfondicarboxylic acid, or their alkyl esters.

[0036] Furthermore, examples of low molecular weight glycols or ester-forming derivatives constituting the aromatic polyester block (x) include aliphatic diols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, and hexamethylene glycol; alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol; and aromatic diols such as 4,4'-dihydroxybiphenyl and 2,2-bis(4'-β-hydroxyethoxyphenyl)propane. Each of these components may be present in one or more forms.

[0037] Among these, block (x) consisting mainly of terephthalic acid and tetramethylene glycol is preferred from the viewpoint of further improving heat resistance, heat fusion properties, and sealing properties. Specifically, it is preferable that the amount of terephthalic acid in the dicarboxylic acid or its ester-forming derivative component be 50 mol% or more, and more preferably 70 mol% or more. Furthermore, it is preferable that the amount of tetramethylene glycol in the low molecular weight glycol or its ester-forming derivative component be 50 mol% or more, and more preferably 70 mol% or more.

[0038] Examples of polyalkylene ether glycols that are the main component of the aliphatic polyether block (y) include polyethylene glycol, polypropylene glycol, polytrimethylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, block or random copolymer of ethylene oxide and propylene oxide, and block random copolymer of ethylene oxide and tetrahydrofuran, which have 1 to 8 carbon atoms, preferably 2 to 6 carbon atoms. Among these, polytetramethylene ether glycol is preferred.

[0039] Here, polyalkylene ether glycol is said to be the main component of aliphatic polyether block (y) to mean that polyalkylene ether glycol is present in aliphatic polyether block (y) in an amount of 50 mol% or more, preferably 70 mol% or more, and more preferably 90 mol% or more.

[0040] Furthermore, the weight-average molecular weight of the polyalkylene ether glycol is preferably 400 to 6,000, more preferably 500 to 4,000, and even more preferably 600 to 3,000.

[0041] Polyester thermoplastic elastomers (TPEEs) can be produced by generating a polyester oligomer from a dicarboxylic acid or its ester-forming derivative and a low molecular weight glycol or its ester-forming derivative, mixing a predetermined amount of polyalkylene ether glycol of a predetermined molecular weight with this polyester oligomer, and copolymerizing it with a tin catalyst or the like.

[0042] For thermoplastic elastomer (A), for example, from the viewpoint of further improving moldability, the MFR value measured under conditions of 230°C and a load of 21N is preferably 0.1g / 10min or more, more preferably 3g / 10min or more, and even more preferably 5g / 10min or more. On the other hand, the MFR value measured under conditions of 230°C and a load of 21N is preferably 15g / 10min or less, more preferably 12g / 10min or less, and even more preferably 10g / 10min or less. The MFR value of thermoplastic elastomer (A) can be measured in accordance with JIS K 7210 (ISO 1133).

[0043] The thermoplastic elastomer (A) is preferably one whose melting point can be observed. From the viewpoint of further improving heat resistance, the melting point of the thermoplastic elastomer (A) is preferably 100°C or higher. On the other hand, from the viewpoint of integral molding with other materials, the melting point of the thermoplastic elastomer (A) is preferably 210°C or lower. The melting point can be measured in accordance with JIS-K7121. Here, if the thermoplastic elastomer (A) has two or more melting points, such as when two or more hard segments are present, the melting point with the highest temperature will be treated as the melting point of the thermoplastic elastomer (A) from the viewpoint of more sufficiently melting the thermoplastic elastomer (A) to form the sealing member. The melting point of the thermoplastic elastomer (A) is a value measured using a differential operating calorimeter (DSC). The thermoplastic elastomer (A) may be used alone or in combination of two or more types, as long as it satisfies the above structure, properties, etc.

[0044] The shape of the thermoplastic elastomer (A) is not particularly limited as long as it can be melt-mixed, and it can be used in powder, granular, or pellet form.

[0045] The content of thermoplastic elastomer (A) in the resin composition is preferably 30% to 97% by mass, more preferably 42% to 95% by mass, and even more preferably 60% to 90% by mass, based on 100% by mass of the total amount of the resin composition. When the content of thermoplastic elastomer (A) is within the above range, the sealing performance of the sealing member can be further improved.

[0046] (Reinforcement material (B)) The reinforcing material (B) used in the present invention is a powdered reinforcing material composed of particles with a Mohs hardness of 5 or less, preferably with a Mohs hardness greater than 3 and less than or equal to 5. The particle shape of the reinforcing material (B) is not particularly limited as long as it improves the strength and rigidity of the resin composition, but examples include a fibrous reinforcing material which is a powder composed of fibrous particles, and a plate-like reinforcing material which is a powder composed of plate-like particles, and a fibrous reinforcing material is preferred. Specific examples of fibrous reinforcing materials include inorganic fibers such as potassium titanate fibers, wollastonite fibers, zinc oxide fibers, basic magnesium sulfate fibers, alumina fibers, silicon carbide fibers, and boron fibers. These reinforcing materials (B) may be used individually or in combination of multiple types.

[0047] From the viewpoint of further suppressing the reduction in the reinforcing effect of the fibrous reinforcing material while further improving abrasion resistance, the average fiber length of the fibrous reinforcing material is preferably 300 μm or less, more preferably 1 μm to 300 μm, even more preferably 1 μm to 200 μm, particularly preferably 3 μm to 100 μm, and most preferably 5 μm to 50 μm. The average aspect ratio of the fibrous reinforcing material is preferably 3 to 200, more preferably 3 to 100, even more preferably 3 to 50, and particularly preferably 3 to 40.

[0048] In this invention, fibrous particles are defined as particles in which L / B and L / T are both 3 or greater, when the longest side of the rectangular parallelepiped with the smallest volume among the rectangular parallelepipeds circumscribed around the particle is defined as the major axis L, the next longest side as the minor axis B, and the shortest side as the thickness T (B>T), with L being the major axis L and L / T being the minor axis B. Plate-like particles are defined as particles in which L / B is less than 3 and L / T is 3 or greater.

[0049] From the viewpoint of further suppressing the reduction in the reinforcing effect of the reinforcing material (B) while further improving wear resistance, the reinforcing material (B) is preferably at least one of potassium titanate fibers and wollastonite fibers, more preferably potassium titanate fibers or wollastonite fibers, and even more preferably potassium titanate fibers.

[0050] Potassium titanate fibers can include, for example, single-crystal fibers represented by the general formula K2O·nTiO2 (where n is an integer from 2 to 8) or K2O·nTiO2·1 / 2H2O (where n is an integer from 2 to 8). Specific examples include 4-potassium titanate fibers, 6-potassium titanate fibers, 8-potassium titanate fibers, and mixtures thereof.

[0051] The dimensions of the potassium titanate fibers are not particularly limited as long as they are within the above-mentioned range, but the average fiber length is preferably 1 μm to 50 μm, more preferably 3 μm to 30 μm, and even more preferably 3 μm to 20 μm. The average fiber diameter is preferably 0.01 μm to 1 μm, more preferably 0.05 μm to 0.8 μm, and even more preferably 0.1 μm to 0.7 μm. The average aspect ratio is preferably 10 or more, more preferably 10 to 100, and even more preferably 15 to 35. These potassium titanate fibers can be commercially available products, for example, "TISMO D" (average fiber length 15 μm, average fiber diameter 0.5 μm) and "TISMO N" (average fiber length 15 μm, average fiber diameter 0.5 μm) manufactured by Otsuka Chemical Co., Ltd. can be used.

[0052] Wollastonite fibers are inorganic fibers made of calcium metasilicate, and conventionally known fibers can be widely used. The dimensions of the wollastonite fibers are not particularly limited as long as they are within the dimensions range of the fibrous reinforcing material described above, but the average fiber length is preferably 5 μm to 180 μm, more preferably 10 μm to 100 μm, and even more preferably 20 μm to 40 μm. The average fiber diameter is preferably 0.1 μm to 15 μm, more preferably 1 μm to 10 μm, and even more preferably 2 μm to 7 μm. The average aspect ratio is preferably 3 or more, more preferably 3 to 30, and even more preferably 3 to 15. These wollastonite fibers can also be commercially available products, for example, "Bystal W" (average fiber length 25 μm, average fiber diameter 3 μm) manufactured by Otsuka Chemical Co., Ltd. can be used.

[0053] The average fiber length and average fiber diameter mentioned above can be measured by observation with a scanning electron microscope, and the average aspect ratio (average fiber length / average fiber diameter) can be calculated from the average fiber length and average fiber diameter. For example, by photographing multiple fibrous reinforcing materials with a scanning electron microscope, 300 fibrous reinforcing materials can be arbitrarily selected from the observed images, their fiber lengths and fiber diameters can be measured, and the average fiber length can be obtained by summing all the fiber lengths and dividing by the number of materials, and the average fiber diameter can be obtained by summing all the fiber diameters and dividing by the number of materials.

[0054] In the present invention, a treatment layer consisting of a surface treatment agent may be formed on the surface of the reinforcing material (B) from the viewpoint of further improving the wettability with the thermoplastic elastomer (A) and further improving the physical properties such as the mechanical properties of the resulting resin composition.

[0055] Examples of surface treatment agents include silane coupling agents and titanium coupling agents. Among these, silane coupling agents are preferred, and amino-based silane coupling agents, epoxy-based silane coupling agents, and alkyl-based silane coupling agents are more preferred. The above surface treatment agents may be used individually or in combination of two or more.

[0056] Examples of amino silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane.

[0057] Examples of epoxy silane coupling agents include 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, triethoxy(3-glycidyloxypropyl)silane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0058] Examples of alkyl silane coupling agents include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane.

[0059] As a method for forming a treatment layer consisting of a surface treatment agent on the surface of the reinforcing material (B), known surface treatment methods can be used. For example, a method can be used in which a surface treatment agent is dissolved in a solvent that promotes hydrolysis (e.g., water, alcohol, or a mixture thereof) to form a solution, and this solution is sprayed onto the reinforcing material (B).

[0060] The amount of surface treatment agent used when treating the surface of the reinforcing material (B) in the present invention is not particularly limited, but for example, the surface treatment agent solution may be sprayed so that the amount of surface treatment agent is between 0.1 parts by mass and 20 parts by mass per 100 parts by mass of reinforcing material (B). By keeping the amount of surface treatment agent within the above range, the adhesion with the thermoplastic elastomer (A) can be further improved, and the dispersibility of the reinforcing material (B) can be further improved.

[0061] In the present invention, from the viewpoint of further suppressing the reduction in the reinforcing effect of reinforcing material (B) while further improving wear resistance, the content of reinforcing material (B) is preferably 0.5% by mass or more, and more preferably 5% by mass or more, relative to the total resin composition. From the viewpoint of not further worsening the sealing performance by excessively increasing the reinforcing effect of reinforcing material (B), the content of reinforcing material (B) is preferably 35% by mass or less.

[0062] In the present invention, the mass ratio of thermoplastic elastomer (A) to reinforcing material (B) contained in the resin composition (thermoplastic elastomer (A) / reinforcing material (B)) is preferably 0.86 to 194, more preferably 1.2 to 190, even more preferably 1.71 to 180, even more preferably 1.71 to 18, particularly preferably 2 to 18, and most preferably 2 to 8.7.

[0063] By setting the mass ratio of the thermoplastic elastomer (A) to the reinforcing material (B) within the above range, the sealing member of the present invention can further suppress the decrease in the reinforcing effect of the reinforcing material (B) while further improving moldability, thereby achieving a higher level of both wear resistance and sealing performance in the sealing member.

[0064] (Silicone resin (C)) The resin composition used in the present invention may optionally contain silicone resin (C). When silicone resin (C) is included, the wear resistance of the sealing material can be further enhanced.

[0065] The silicone resin (C) used in the present invention is an oligomer or polymer having an organic group with a siloxane bond as its main backbone. Examples of the above silicone resins include silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carbinol-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, methylhydrogen silicone oil, mercapto-modified silicone oil, methacrylic-modified silicone oil, polyether-modified silicone oil, aralkyl-modified silicone oil, fluoroalkyl-modified silicone oil, long-chain alkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, and phenyl-modified silicone oil; silicone rubber having a structure in which linear dimethylpolysiloxane is crosslinked; and siloxane bonds (CH3SiO 3 / 2 ) n Examples include polymethylsilsesquioxane having a three-dimensional network-like cross-linked structure, and silicone resins with a three-dimensional network structure mainly composed of trifunctional siloxane units.

[0066] A specific example of silicone resin (C) is the silicone resin represented by the following general formula (1).

[0067] [ka]

[0068] In general formula (1), R 1 R represents an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, or an aryl group, and these groups may have substituents. 1 l and m may be identical or different from each other. l and m represent any integer greater than or equal to 1. The order in which each repeating unit structure within the parentheses is joined is not particularly limited.

[0069] R 1Examples of the alkyl group represented by include a linear or branched alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and the like.

[0070] R 1 Examples of the cycloalkyl group represented by include a cycloalkyl group having 3 to 10 carbon atoms. Specific examples include, for example, cyclopropyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like.

[0071] R 1 Examples of the alkenyl group represented by include a linear or branched alkenyl group having 2 to 20 carbon atoms, preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include, for example, vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl, 2-butenyl group, pentenyl group, hexenyl, heptenyl group and the like.

[0072] R 1 Examples of the cycloalkenyl group represented by include a cycloalkenyl group having 3 to 10 carbon atoms. Specific examples include, for example, cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group and the like.

[0073] R 1 Examples of the aryl group represented by include an aryl group having 6 to 20 carbon atoms, preferably an aryl group having 6 to 12 carbon atoms. Specific examples include, for example, phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group and the like.

[0074] R 1The groups indicated by may each have substituents. Examples of such substituents include amino groups, aryl groups (e.g., phenyl groups), or amino groups substituted with lower amino alkyl groups (e.g., C2-C6, preferably C2-C4), epoxy groups, glycidoxy groups, mercapto groups, carboxyl groups, ether groups, epoxycycloalkyl groups (e.g., 3,4-epoxycyclohexyl groups), hydroxyl groups, isocyanate groups, ester groups (e.g., C1-C20 alkoxycarbonyl groups), (meth)acryloyloxy groups, ureido groups ( Examples include -NHCONH2), carbamoyl groups (-CONH2), alkanoylamino groups (e.g., alkanoylamino groups with 1 to 20 carbon atoms), alkanoyloxy groups (e.g., alkanoyloxy groups with 1 to 20 carbon atoms), cycloalkyl groups (e.g., cyclopentyl groups, cyclohexyl groups), cycloalkenyl groups (e.g., cyclopentenyl groups, cyclohexenyl groups), aryl groups (e.g., phenyl groups), halogen atoms (e.g., fluorine atoms, chlorine atoms, bromine atoms, etc.).

[0075] R 1 Suitable specific examples of the group shown include, for example, the group represented by the following general formulas (2a) to (2g).

[0076] [ka]

[0077] In general formulas (2a) to (2g), a to g may be the same or different, and represent integers from 2 to 6. Preferably, a to g represent 2 or 3.

[0078] l is preferably an integer from 1 to 20,000, more preferably an integer from 1 to 10,000. m is preferably an integer from 1 to 20,000, more preferably an integer from 1 to 10,000. The silicone resin represented by the above general formula (1) is preferably the silicone resin represented by the general formula (3).

[0079] [ka]

[0080] In general formula (3), R 1A l and m are alkyl groups substituted with 1 to 3 groups selected from the group consisting of an amino group, a phenyl group, or an amino group having 2 to 4 carbon atoms, an epoxy group, a glycidoxy group, a carboxyl group, a hydroxyl group, an isocyanate group, and an epoxycyclohexyl group. l and m are the same as in general formula (1) above. The order of bonding in each repeating unit structure within parentheses is not particularly limited.

[0081] R 1A Even so, R in the above general formula (1) 1 It is preferable that the group is one of the examples provided, and more preferably a group represented by general formulas (2a) to (2g).

[0082] Among the silicone resins represented by the above general formula (1), another preferred example is the silicone resin represented by the general formula (4).

[0083] [ka]

[0084] In general formula (4), R 1B l and m are alkyl groups substituted with 1 to 3 groups selected from the group consisting of a phenyl group, an amino group, an amino group substituted with a C2-C4 alkyl group, an epoxy group, a glycidoxy group, a carboxyl group, a hydroxyl group, an isocyanate group, and an epoxycyclohexyl group. l and m are the same as in general formula (1) above. The order of bonding in each repeating unit structure within parentheses is not particularly limited.

[0085] R 1B Even so, R in the above general formula (1) 1 It is preferable that the group is one of the examples provided, and more preferably a group represented by general formulas (2a) to (2g).

[0086] When the silicone resin represented by general formula (1) is a liquid (for example, silicone oil), the viscosity (at 25°C) is typically 10 mm. 2 / s~2,000mm 2 / s, preferably 10mm 2 / s~1,000mm 2 The viscosity is / s. When the viscosity is within this range, the viscosity difference with the thermoplastic elastomer can be reduced during melt mixing, making it easier to achieve uniform dispersion. Viscosity can be measured using a kinematic viscosity analyzer.

[0087] Furthermore, from the viewpoint of further improving workability and further suppressing bleeding from the resin composition, it is preferable to use a silicone resin in which the above-mentioned silicone resin is supported on a porous fine particle carrier such as silica (silicon dioxide).

[0088] Furthermore, carbonates such as calcium carbonate and barium carbonate, silicates such as calcium silicate, barium silicate, and magnesium silicate, phosphates such as calcium phosphate, barium phosphate, magnesium phosphate, zirconium phosphate, and apatite, metal oxides such as alumina, graphite, zeolite, layered clay minerals, polyethylene, polyurethane, cellulose, polyamide, polyvinyl formal, phenolic resin, epoxy resin, urea resin, etc. may be used as carriers.

[0089] Of these, fumed silica, precipitated silica, finely ground silica, and / or calcined silica are preferably used as the silica carrier, and fumed silica is more preferably used as the silica carrier. The fumed silica content in the silicone resin (C) is preferably 20% to 40% by mass, more preferably 25% to 35% by mass, and even more preferably 28% to 32% by mass, when the total amount of silicone resin and fumed silica is 100% by mass. When the fumed silica content is within the above range, the abrasion resistance (abrasion resistance between resins) can be further enhanced when the sealing member of the present invention is used in applications involving sliding with resin.

[0090] When the silicone resin represented by general formula (1) is a solid (for example, polymethylsilsesquioxane, silicone resin, etc.), its shape is not particularly limited as long as it can be melt-mixed, and it can be used in powder, granular, or pellet form.

[0091] These silicone resins (C) include both commercially available known compounds and compounds that can be produced using methods known to those skilled in the art. As will be described later, for example, a resin composition can be obtained by mixing and heating (especially by melt kneading) the silicone resin (C) together with a thermoplastic elastomer (A) and a reinforcing material (B).

[0092] In the resin composition used in the present invention, the content of silicone resin (C) is preferably 0.1% by mass or more and 8% by mass or less, more preferably 0.3% by mass or more and 7% by mass or less, and particularly preferably 0.5% by mass or more and 6% by mass or less, based on 100% by mass of the total amount of the resin composition. If the amount of silicone resin (C) is less than 0.1% by mass, the abrasion resistance of the sealing member may not be obtained, and if it is more than 8% by mass, the abrasion resistance of the sealing member may decrease.

[0093] In addition, the resin composition used in the present invention may use one of the above-mentioned silicone resins (C) alone, or it may be used as a mixture of two or more types.

[0094] The resin composition used in the present invention can further improve abrasion resistance by containing a silicone resin with a siloxane bond as its main backbone in a thermoplastic elastomer.

[0095] (Other additives) The resin composition of the present invention may contain other additives as long as it does not impair its desirable physical properties. Other additives include thermoplastic resins and thermosetting resins other than thermoplastic elastomer (A) and silicone resin (C); inorganic fillers other than reinforcing material (B) (e.g., calcium carbonate, mica, sericite, illite, talc, kaolinite, montmorillonite, boehmite, smectite, vermiculite, palygorskite, pyrophyllite, hydrosite, diatomaceous earth, titanium dioxide, etc.); conductive fillers (e.g., metal particles (e.g., aluminum flakes), metal fibers, metal oxide particles, carbon fibers, ionic liquids, surfactants, etc.); antistatic agents (e.g., anionic antistatic agents, cationic antistatic agents, nonionic antistatic agents, etc.); antioxidants and heat stabilizers (e.g., hindered phenols, hydroquinones, phosphites and their derivatives, etc.); ultraviolet absorbers (e.g., resorcinols, salicylates, benzotriazoles, benzo Examples of such agents include: phenones, triazines, etc.; light stabilizers (e.g., hindered phenols, etc.); weathering agents; lightfastening agents; mold release agents (e.g., higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts (where higher fatty acids refer to those with 10 to 25 carbon atoms), fatty acids, fatty acid metal salts, etc.); lubricants; flow modifiers; plasticizers (e.g., polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, phosphate ester plasticizers, polyalkylene glycol plasticizers, epoxy plasticizers); impact modifiers; flame retardants (e.g., phosphazene compounds, phosphate esters, condensed phosphate esters, inorganic phosphorus-based, halogen-based, silicone-based flame retardants, metal oxide-based flame retardants, metal hydroxide-based flame retardants, organometallic salt-based flame retardants, nitrogen-based flame retardants, boron compound-based flame retardants, etc.); dripping inhibitors; nucleating agents; dispersants; vibration damping agents; neutralizing agents; blocking inhibitors, etc. Other additives may contain one or more of these.

[0096] If the resin composition used in the present invention contains other additives, the amount of these additives is not particularly limited, as long as it does not impair the desirable physical properties of the sealing member of the present invention. The amount of other additives is preferably 10% by mass or less, more preferably 5% by mass or less, of the total amount of the resin composition (100% by mass).

[0097] <Method for producing the resin composition used in the present invention> The resin composition used in the present invention can be produced by heating and mixing (especially by melt kneading) a mixture containing a thermoplastic elastomer (A), a powdery reinforcing material (B) composed of particles with a Mohs hardness of 5 or less, and optionally a silicone resin (C) and other additives.

[0098] For melt mixing, known melt mixing equipment such as a twin-screw extruder can be used. Specifically, it can be manufactured by (1) pre-mixing each component in a mixer (tumbler, Henschel mixer, etc.), melt mixing in a melt mixing equipment, and pelletizing with pelletizing means (pelletizer, etc.); (2) preparing a masterbatch of the desired components, mixing in other components as needed, melt mixing in a melt mixing equipment, and pelletizing; or (3) supplying each component to a melt mixing equipment and pelletizing.

[0099] The processing temperature in melt kneading is not particularly limited as long as it is a temperature at which the thermoplastic elastomer (A) can melt. Typically, the cylinder temperature of the melt kneading apparatus used for melt kneading is adjusted to this range. Thus, the resin composition of the present invention that exhibits the desired effect is produced.

[0100] <Method of manufacturing and application of the seal member of the present invention> The resin composition of the present invention can be formed into a sealing member by known resin molding methods such as injection molding, insert molding, compression molding, blow molding, inflation molding, and co-extrusion molding, depending on the type, application, and shape of the sealing member to be intended. Injection molding and insert molding are preferred as resin molding methods. Furthermore, a molding method combining the above molding methods can be employed.

[0101] By employing the above-described method for manufacturing the resin composition and molding it, and by setting the Type A durometer hardness of the sealing member to greater than 60 and less than 90, the sealing member of the present invention is manufactured, which can achieve a high level of both wear resistance and sealing performance.

[0102] The flexibility or hardness of the sealing member of the present invention can be expressed as a Type A durometer hardness or a Type D durometer hardness measured in accordance with JIS K 6253-3:2012. The Type A durometer hardness is preferably greater than 60, more preferably 70 or higher, more preferably 75 or higher, even more preferably 80 or higher, particularly preferably greater than 80, and less than 90. The Type D durometer hardness is preferably greater than 12, more preferably 17 or higher, even more preferably 20 or higher, particularly preferably 24 or higher, preferably less than 30, and more preferably 25 or lower.

[0103] The Type A and Type D durometer hardness of the sealing member can be adjusted, for example, by the type and content of the thermoplastic elastomer (A), or the type and content of the reinforcing material (B).

[0104] The sealing member of the present invention, in particular when used as a sealing member for the moving parts of devices and components, can improve both wear resistance and sealing performance, and moreover, it has the advantage of being less likely to create voids inside the sealing member, and therefore having excellent sealing properties for liquid reservoirs and being less likely to leak fluid. In particular, even when used in applications involving sliding with resin, it can achieve a high level of both wear resistance (wear resistance between resins) and sealing performance. For this reason, it can be applied to known gasket applications such as the sheet-type gasket that seals the wells of a microchip used in digital PCR described in Japanese Patent Application Publication No. 2020-051574, and the gasket used in the plunger part of the syringe conduit of a sample liquid injection device described in Japanese Patent Application Publication No. 2014-098595. [Examples]

[0105] The present invention will be described in detail below based on examples and comparative examples, but is not limited thereto, as long as the gist of the invention is not lost. The raw materials used in these examples and comparative examples are as follows.

[0106] Polyester thermoplastic elastomer (TPEE): Type A durometer hardness (after 15 seconds): 61, MFR value (230℃, 21N) 6g / 10min (manufactured by Mitsubishi Chemical Corporation, product name "Tefablock A1500") Silicone resin: Silicone additive for thermoplastic resins (manufactured by Asahi Kasei Wacker Silicone Co., Ltd., product name "GENIOPLAST(registered trademark) PelletS", fumed silica content: 30% by mass) Potassium titanate fiber: Average fiber length 15 μm, average fiber diameter 0.5 μm, Mohs hardness: 4 (manufactured by Otsuka Chemical Co., Ltd., product name "Tismo N102") Wollastonite fiber: Average fiber length 25 μm, average fiber diameter 3 μm, Mohs hardness: 4.5 (manufactured by Otsuka Chemical Co., Ltd., product name "Vistal W") Glass fiber: (Manufactured by Nippon Electric Glass Co., Ltd., product name "ECS03 T-289", average fiber length 3 mm, average fiber diameter 16 μm, Mohs hardness: 6)

[0107] <Examples 1-9 and Comparative Examples 1-3> The materials were melt-mixed using a twin-screw extruder according to the mixing ratios shown in Table 1 to produce pellet-shaped resin compositions. The cylinder temperature of the twin-screw extruder was 180°C.

[0108] The obtained resin composition was used to produce friction and abrasion test specimens (hollow cylinders with an outer diameter of 25.6 mm, an inner diameter of 20 mm, and a height of 15 mm) and sealing performance test specimens (plate-shaped specimens with a long side of 90 mm, a short side of 50 mm, and a thickness of 3 mm) by injection molding. The cylinder temperature of the injection molding machine was 200°C, and the mold temperature was 40°C.

[0109] <Rating> (Friction and wear test) For the friction and abrasion test specimens prepared as described above, the specific wear amount (abrasion volume of the specimen itself) and the specific wear amount of the mating material (abrasion volume of the mating material) were measured using a Suzuki friction and abrasion tester (EFM-III-F, manufactured by A&D Company, Limited) in accordance with JIS K7218 Method A. The test conditions were a surface pressure of 0.12 MPa, a peripheral speed of 0.1 m / sec, 10 seconds of sliding followed by 10 seconds of rest, repeated for 100 cycles, with the mating material being a hollow cylinder (material: polycarbonate resin, manufactured by SABIC, product name "Lexan 121R", outer diameter 25.6 mm, inner diameter 20 mm, height 15 mm).

[0110] (Method for measuring durometer hardness) Type A and Type D durometer hardness were measured in accordance with JIS K 6253-3:2012. For the Type A durometer, a Muratec KDS product, model number "Rubber Hardness Tester Type A Standard Model DM-104A," was used. For the Type D durometer, a Ueshima Seisakusho product, model number "UF.SHORE.S DUROMETER TYPE D," was used.

[0111] (Evaluation of sealing performance) A 10 mL burette containing 10 mL of water was placed vertically on the seal performance evaluation specimen prepared as described above. After applying a 300 g load, the stopcock of the burette was opened, and it was observed whether water leaked from the seal performance evaluation specimen. The criteria for evaluating the seal performance were to leave the specimen for 30 seconds after opening the stopcock and evaluate whether water leaked from the seal performance evaluation specimen. For evaluation, the amount of water leaked from the tip of the burette was measured, and a leak of 0.1 ml or less was marked as ○, and a leak of more than 0.1 ml was marked as ×.

[0112] (Evaluation of bending strength) In accordance with JIS K7171, the bending strength was measured using an Autograph AG-5000 (manufactured by Shimadzu Corporation) in a three-point bending test with a support distance of 60 mm.

[0113] [Table 1]

[0114] As is clear from Table 1, in the sealing members of Examples 1 to 9, which contain a thermoplastic elastomer (A) and a reinforcing material (B) with a Mohs hardness of 5 or less, and whose Type A durometer hardness is in the range of greater than 60 and less than 90, the self-material wear volume and the mating material (resin) wear volume are reduced, and good sealing performance is also evaluated. On the other hand, in the sealing members of Comparative Examples 1 to 3, whose Type A durometer hardness is greater than 60 and not less than 90, the self-material wear volume and the mating material (resin) wear volume are not sufficiently reduced, and in the case of Comparative Examples 2 and 3, good sealing performance is not evaluated. From these results, it was found that the sealing members of the present invention have the unexpected effect of being able to improve both wear resistance (especially the wear resistance between resins) and sealing performance.

[0115] Accordingly, a sealing member made of a thermoplastic elastomer resin composition containing the thermoplastic elastomer (A) of the present invention and a reinforcing material (B) having a Mohs hardness of 5 or less, and characterized by a Type A durometer hardness greater than 60 and less than 90, exhibits excellent wear resistance and sealing properties, and offers a high degree of freedom in product design that enables both to be achieved simultaneously. Therefore, it is possible to improve both wear resistance and sealing properties in moving parts, and moreover, voids are less likely to form inside the sealing member, making it suitable for use in parts and devices where liquid sealing is required.

Claims

1. In a sealing member made of a molded resin composition, The resin composition contains a thermoplastic elastomer (A), a reinforcing material (B) having a Mohs hardness of 5 or less, and a silicone resin (C). The content of fumed silica in the silicone resin (C) is 20% by mass or more and 40% by mass or less. A sealing member characterized in that, when the durometer hardness of the sealing member is measured in accordance with JIS K 6253-3:2012, the Type A durometer hardness is greater than 60 and less than 90.

2. The sealing member according to claim 1, characterized in that the reinforcing material (B) is a fibrous reinforcing material.

3. The sealing member according to claim 2, characterized in that the average fiber length of the fibrous reinforcing material is 1 μm to 300 μm.

4. The sealing member according to claim 2 or 3, characterized in that the fibrous reinforcing material is an inorganic fiber.

5. The sealing member according to claim 2 or 3, characterized in that the fibrous reinforcing material is at least one of potassium titanate fibers and wollastonite fibers.

6. The sealing member according to claim 1 or claim 2, wherein the thermoplastic elastomer (A) is a polyester-based thermoplastic elastomer.

7. The sealing member according to claim 1 or claim 2, wherein the resin composition contains 60% to 90% by mass of the thermoplastic elastomer (A) and 5% to 35% by mass of the reinforcing material (B).

8. The sealing member according to claim 1 or claim 2, wherein the content of the silicone resin (C) in the resin composition is 0.1% by mass to 8% by mass.

9. A sealing member according to claim 1 or claim 2, used in applications involving sliding with resin.

10. A sealing member according to claim 1 or claim 2, which is a medical sealing member.

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