Resin needle

Abstract

To provide a resin needle with excellent fine moldability, puncture properties, and heat resistance. [Solution] According to the present invention, a resin needle made of a resin composition is provided, wherein the resin composition comprises polylactic acid and non-fibrous inorganic particles, the polylactic acid having a weight-average molecular weight of 20,000 to 400,000 and a D-isomer ratio of 15% by mass or less or 85% by mass or more, the non-fibrous inorganic particles having an average particle size of 0.05 to 20 μm, and the content of the non-fibrous inorganic particles is 5 to 70 parts by mass per 100 parts by mass of polylactic acid.

Description

Technical Field

[0001] The present invention relates to a resin needle made of a resin composition.

Background Art

[0002] Patent Document 1 discloses a medical needle having a fine structure.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, polylactic acid is cited as an example of the polymer that constitutes a medical needle. Since polylactic acid has a glass transition temperature of about 60°C, it has poor heat resistance, and there is a problem that the fine structure collapses in a high-temperature environment and the puncture performance cannot be maintained. Further, although the heat resistance is improved by crystallizing polylactic acid, there are problems such as embrittlement and the need for time for crystallization, resulting in a decrease in productivity.

[0005] The present invention has been made in view of such circumstances, and provides a resin needle excellent in fine moldability, puncture property, and heat resistance.

Means for Solving the Problems

[0006] According to the present invention, the following inventions are provided. [1] A resin needle made of a resin composition, wherein the resin composition contains polylactic acid and non-fibrous inorganic particles, the polylactic acid has a weight average molecular weight of 20,000 to 400,000 and a D-form ratio of 15% by mass or less or 85% by mass or more, the non-fibrous inorganic particles have an average particle diameter of 0.05 to 20 μm, and the content of the non-fibrous inorganic particles is 5 to 70 parts by mass with respect to 100 parts by mass of the polylactic acid. A resin needle according to [2][1], wherein the resin composition contains a biocompatible resin other than polylactic acid, and the content of the biocompatible resin is 50 parts by mass or less per 100 parts by mass of polylactic acid. A resin needle according to [3][1] or [2], wherein the degree of crystallinity of the polylactic acid component of the resin needle is 1 to 60%. A resin needle according to any one of [4][1] to [3], wherein the crystallization temperature of the polylactic acid component of the resin needle is greater than 80°C. A resin needle according to any one of [5][1] to [4], wherein the resin composition is extruded at a melting temperature of 220°C and has a length of 50 mm and a cross-sectional area of ​​3 mm. 2 A resin needle in which the strand is preheated in an 80°C environment for 5 minutes and subjected to a tensile test at 1 mm / min, with an 80°C modulus of elasticity of 10 MPa or more. A resin needle according to any one of [6][1] to [5], wherein the resin composition is extruded at a melting temperature of 220°C and has a length of 50 mm and a cross-sectional area of ​​3 mm. 2 A resin needle in which the strand is subjected to a tensile test at 1 mm / min in a 23°C environment, and the 23°C elongation is measured to be 1% or more. A resin needle according to any one of [7][1] to [6], wherein the non-fibrous inorganic particles are layered minerals. A resin needle as described in [8][7], wherein the layered mineral is talc. A resin needle as described in any one of [9][1] to [8], wherein the resin needle is a medical needle. [Effects of the Invention]

[0007] Through diligent research, the inventors discovered that the resin needle of the present invention exhibits excellent micro-molding properties, puncture properties, and heat resistance, leading to the completion of the present invention. [Brief explanation of the drawing]

[0008] [Figure 1] The shape of the resin needle 1 manufactured in the examples and comparative examples is shown. [Figure 2] Figure 1 shows the detailed structure of the puncture portion 10 of the resin needle 1, with Figure 2A being a perspective view, Figure 2B a front view, and Figure 2C a plan view. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature constitutes an independent invention.

[0010] 1. Uses, structure, and manufacturing method of resin needles The resin needle of one embodiment of the present invention can be used for any application involving puncture of an object, which may be a living organism or a non-living organism. Preferably, the resin needle is a medical needle used for medical purposes.

[0011] The shape of the resin needle is not particularly limited as long as it has a puncturing portion that has the ability to puncture, and it may have a hollow structure or a solid structure. The puncturing portion of the resin needle may have a simple structure that tapers towards the tip, or it may have a complex shape as disclosed in Patent Document 1. Preferably, the resin needle is equipped with a holder that is shaped to fit the casing of the puncture device that holds the resin needle.

[0012] The radius of curvature of the tip of the puncture site is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 10 μm or less. This radius of curvature is, for example, 0.1 to 100 μm, specifically, for example, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100 μm, and may be in the range between any two of the values ​​exemplified here.

[0013] In order to achieve excellent puncture performance, the resin needle needs to have a sharp tip and is desired to have excellent micro-molding performance. Also, the resin needle may be exposed to a high-temperature environment during storage, sterilization, etc., and it is desired that the puncture performance is not impaired even in a high-temperature environment. The resin needle of the present embodiment can solve these problems by being composed of a resin composition having the following composition.

[0014] The resin needle can be manufactured by molding the following resin composition by a method such as injection molding.

[0015] 2. Composition of the resin needle The resin needle is made of a resin composition. This resin composition contains polylactic acid and non-fibrous inorganic particles.

[0016] Polylactic acid is a polymer containing constituent components derived from lactic acid. The polylactic acid used in the resin composition of the present embodiment has a weight-average molecular weight of 20,000 to 400,000, preferably 50,000 to 300,000, and more preferably 100,000 to 250,000. If the weight-average molecular weight is too small, the puncture performance tends to deteriorate, and if the weight-average molecular weight is too large, the micro-molding performance tends to deteriorate. Specifically, this weight-average molecular weight is, for example, 20,000, 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, and may be in the range between any two of the values exemplified here. The weight-average molecular weight can be measured by gel permeation chromatography (GPC) method.

[0017] Lactic acid includes L-lactic acid and D-lactic acid, and polylactic acid contains one or both of the L-form component derived from L-lactic acid and the D-form component derived from D-lactic acid. The polylactic acid used in the resin composition of this embodiment has a D-form ratio of 15% by mass or less or 85% by mass or more, more preferably 12% by mass or less or 90% by mass or more, and even more preferably 10% by mass or less or 95% by mass or more. The D-form ratio is the ratio of the D-form component when the total of the L-form component and the D-form component is 100% by mass. The closer the D-form ratio is to 50% by mass, the more difficult it is for polylactic acid to crystallize. When the D-form ratio exceeds 15% by mass or is less than 85% by mass, the crystallinity may become too low. Specifically, for example, the D-form ratio is 0, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15% by mass, and it may be in the range between any two of the values exemplified here or any value below. Also, specifically, for example, the D-form ratio is 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 100% by mass, and it may be in the range between any two of the values exemplified here or any value above. The D-form ratio of the polylactic acid resin can be determined according to the method for measuring the D-form content described in "Voluntary Standards for Synthetic Resin Food Containers and Packaging, etc. such as Polyolefins, 3rd Edition Revised Edition, Supplement in June 2004, Part 3, Hygiene Test Methods, P12-13". Specifically, the method for measuring the D-form ratio of the polylactic acid resin is as follows.

[0018] First, add sodium hydroxide / methanol to accurately weighed polylactic acid, set it in a water bath shaker set at 65°C, and perform hydrolysis until the resin component becomes a uniform solution. Then, add dilute hydrochloric acid to the alkali solution after the hydrolysis is completed to neutralize it. After making the decomposition solution constant volume with pure water, separate a certain volume into a volumetric flask and dilute it with the mobile phase solution of high performance liquid chromatography (HPLC), adjust the pH to be in the range of 3 to 7, quantitatively fill the volumetric flask, and filter it with a membrane filter (0.45 μm). The D-form ratio of the polylactic acid resin can be determined by quantifying D-lactic acid and L-lactic acid in this adjusted solution by HPLC.

[0019] Non-fibrous inorganic particles are inorganic particles that are not fibrous. If fibrous inorganic particles are incorporated into a resin composition, there is a risk that they may cause tumors if they remain on the skin. Therefore, the inorganic particles incorporated into the resin composition are non-fibrous. Examples of non-fibrous inorganic particles include layered minerals having a layered structure, such as talc and mica, and non-layered minerals that do not have a layered structure, such as calcium carbonate and hydroxyapatite. When non-fibrous inorganic particles contain layered minerals, the heat resistance tends to be good, so it is preferable that the non-fibrous inorganic particles contain layered minerals. Furthermore, when the layered mineral is talc, the heat resistance tends to be particularly high, so it is preferable that the layered mineral is talc.

[0020] The non-fibrous inorganic particles have an average particle size of 0.05 to 20 μm, preferably 0.1 to 10 μm, and more preferably 0.2 to 8 μm. If the average particle size is too small, the heat resistance tends to be poor, and if the average particle size is too large, the fine moldability tends to be poor. Specifically, this average particle size is, for example, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 μm, and may also be in the range between any two of the values ​​exemplified here. The average particle size refers to the particle size at 50% of the integrated value in the particle size distribution determined by laser diffraction and scattering, and can be measured using JIS R1629 "Method for measuring particle size distribution of fine ceramic raw materials by laser diffraction and scattering".

[0021] The content of non-fibrous inorganic particles is 5 to 70 parts by mass per 100 parts by mass of polylactic acid. If the content is too low, the heat resistance of the resin needle tends to be poor, and if the content is too high, the fine moldability tends to be poor. The content of non-fibrous inorganic particles per 100 parts by mass of polylactic acid is preferably 8 parts by mass or more, more preferably 15 parts by mass or more, and still more preferably 20 parts by mass or more. Furthermore, this content is preferably 60 parts by mass or less, more preferably 43 parts by mass or less, and still more preferably 35 parts by mass or less. Specifically, this content is, for example, 5, 8, 10, 15, 20, 25, 30, 35, 40, 43, 45, 50, 55, 60, 65, and 70 parts by mass, and may be in the range between any two of the values ​​exemplified here.

[0022] The resin composition of this embodiment may also contain biocompatible resins other than polylactic acid. Biocompatible resins refer to resins that have low toxicity to cells and high affinity with living organisms (humans and animals). Examples of such resins include polycarbonate, poly(meth)acrylic acid ester, polyvinyl chloride, polyethylene glycol, parylene, polyethylene, polypropylene, silicone, polyisoprene, fluororesin, polyetherimide, polyethylene oxide, polyethylene terephthalate, polyethylene succinate, polybutylene terephthalate, polybutylene succinate, polybutylene succinate carbonate, polyphenylene oxide, polyphenylene sulfide, polyformaldehyde, polyanhydride, polyamide (nylon 6, nylon 66), polybutadiene, polyvinyl acetate, polyvinyl alcohol, polyvinylpyrrolidone, polyesteramide, polyacrylonitrile, polysulfone, polyethersulfone, ABS resin, polyurethane (polyetherurethane, polyesterurethane, polyetherurethane urea), polyvinylidene chloride, polystyrene, polyacetal, polybutadiene, ethylene vinyl acetate copolymer, and ethylene vinyl alcohol copolymer. Combination, ethylene propylene copolymer, polyhydroxyethyl methacrylate, polyhydrobutylate, polyoltoester, polyglycol, polycaprolactone, polylactic acid copolymer, polyglycolic acid-glycol copolymer, polycapronolactone copolymer, polydioxanone, perfluoroethylene-propylene copolymer, cyanoacrylate polymer, polybutylcyanoacrylate, polyaryl ether ketone, epoxy resin, polyester resin, polyimide, phenolic resin), cellulose Examples include sugars, starch, chitin / chitosan, agar, carrageenan, alginic acid, agarose, pullulan, mannan, curdlan, xanthan gum, gellan gum, pectin, xyloglucan, guar gum, lignin, oligosaccharides, hyaluronic acid, schizophyllan, lentinan, collagen, gelatin, keratin, fibroin, glue, sericin, plant proteins, milk proteins, lan proteins, synthetic proteins, heparin, nucleic acids, sugars, candy, glucose, maltose, sucrose, and polymer alloys thereof.However, preferably, from the viewpoint of heat resistance, a resin with a softening point exceeding 80°C is preferred. Examples of poly(meth)acrylic acid esters include polymethyl methacrylate. The content of the biocompatible resin is preferably 50 parts by mass or less per 100 parts by mass of polylactic acid. If the content of the biocompatible resin is too high, the fine moldability tends to deteriorate. The content of the biocompatible resin per 100 parts by mass of polylactic acid is, for example, 1 to 50 parts by mass, specifically, for example, 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 parts by mass, and may be in the range between any two of the values ​​exemplified here or less than or equal to either of them.

[0023] 3. Physical properties of resin needles and resin compositions The resin needle has a polylactic acid component crystallinity of 1-60%, preferably 3-55%, and more preferably 5-45%. If the crystallinity is too low, the heat resistance tends to be insufficient. If the crystallinity is too high, the resin needle tends to break easily, resulting in insufficient puncture performance. Specifically, the crystallinity can be, for example, 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60%, and may also be in a range between any two of the values ​​exemplified here.

[0024] The crystallization temperature of the polylactic acid component of the resin needle is preferably above 80°C. In this case, the crystallization degree of the resin needle does not unintentionally increase, which can impair the flexibility of the resin needle. This crystallization temperature is, for example, 81 to 105°C, specifically, for example, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, and 105°C, and may also be in the range between any two of the values ​​exemplified here.

[0025] The degree of crystallinity and crystallization temperature of the polylactic acid component of the resin needle can be measured by differential scanning calorimetry, as will be described in detail in the examples.

[0026] The resin composition of this embodiment preferably has an 80°C modulus of 10 MPa or higher. If this value is too low, the heat resistance will decrease, the resin needle will be prone to deformation in high-temperature environments, and its puncture performance will be poor when it returns to room temperature. The 80°C modulus is, for example, 10 to 140 MPa, specifically, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, and 140 MPa, and may also be in the range between any two of the values ​​exemplified here.

[0027] The resin composition of this embodiment preferably has a 23°C elongation of 1% or more. If this value is too low, the puncture properties tend to be poor. The 23°C elongation is, for example, 1 to 20%, specifically, for example, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 11, 12, 12.5, 15, and 20%, and may be in the range between any two of the values ​​exemplified here.

[0028] The 80°C modulus of elasticity and the 23°C elongation can be measured by the method shown in the examples. [Examples]

[0029] 1. Preparation of materials The materials shown in Tables 1 to 3 were prepared for the manufacture of resin needles.

[0030] <Polylactic acid> PLLA (poly-L-lactic acid) and PDLA (poly-D-lactic acid) shown in Table 1 were prepared by the following manufacturing method. [Manufacturing Example 1-1] 100 parts by weight of L-lactide was charged into a reactor equipped with a stirrer, nitrogen gas inlet tube, thermometer, and vacuum device. The contents were heated to 190°C while nitrogen gas was introduced into the reactor. 0.15 parts by weight of stearyl alcohol and 0.005 parts by weight of tin octate were added, and polymerization was carried out at 190°C for 2 hours. Finally, the pressure was reduced to below 10 Pa to remove the monomers, and the mixture was pelletized to obtain poly-L-lactic acid (PL-1). [Manufacturing Example 1-2] Poly-L-lactic acid (PL-2) was obtained by performing the same procedure as in Production Example 1-1, except that the amount of stearyl alcohol was changed to 0.1 parts by weight. [Manufacturing Examples 1-3] Poly-L-lactic acid (PL-3) was obtained by performing the same procedure as in Production Example 1-1, except that the amount of stearyl alcohol was changed to 0.6 parts by weight. [Manufacturing Examples 1-4] Poly-L-lactic acid (PL-4) was obtained by performing the same procedure as in Production Example 1-1, except that the amount of L-lactide was changed to 88 parts by weight and the amount of D-lactide to 12 parts by weight. [Manufacturing Examples 1-5] Poly-L-lactic acid (PL-5) was obtained by performing the same procedure as in Production Example 1-1, except that the amount of stearyl alcohol was changed to 3 parts by weight. [Manufacturing Examples 1-6] Poly-L-lactic acid (PL-6) was obtained by performing the same procedure as in Production Example 1-1, except that the amount of stearyl alcohol was changed to 0.07 parts by weight. [Manufacturing Examples 1-7] Poly-L-lactic acid (PL-7) was obtained by performing the same procedure as in Production Example 1-1, except that the amount of L-lactide was changed to 80 parts by weight and the amount of D-lactide to 20 parts by weight. [Manufacturing Examples 1-8] Poly-D-lactic acid (PL-8) was obtained by performing the same procedure as in Production Example 1-1, except that 100 parts by weight of D-lactide was replaced with L-lactide.

[0031] <Non-fibrous inorganic particles> • Talc (hydrated magnesium silicate) [Manufacturing Example 2-1] Talc rough was coarsely crushed to a particle size of 1 cm or less using a jaw crusher, and then finely crushed and classified using a pulperizer, an impact-type pulverizer with a built-in classifier. Next, it was classified using a flume classifier to obtain talc (T-1). [Manufacturing Example 2-2] The talc powder was recovered before classification using the elutriation classifier in Production Example 2-1 to obtain talc (T-2). [Manufacturing Example 2-3] The talc (T-1) obtained in Production Example 2-2 was pulverized by dry jet pulverization to obtain talc (T-3). [Manufacturing Example 2-4] The talc (T-1) obtained in Production Example 2-1 was pulverized by dry jet milling to obtain talc (T-4). [Manufacturing Example 2-5] Talc ore was coarsely crushed to a particle size of 1 cm or less using a jaw crusher, and then finely crushed using a VX mill to obtain talc (T-5).

[0032] • Mica M-1: Manufactured by Sunes Ointment Co., Ltd., Model SJ-005 • Calcium carbonate C-1: Manufactured by Asahi Mining Co., Ltd., model MC-140 • Hydroxyapatite A-1: ​​Manufactured by Taihei Chemical Industry Co., Ltd., Model HAP-200

[0033] <Other biocompatible resins> • Polycarbonate PC-1: Manufactured by Mitsubishi Engineering Plastics Co., Ltd., model S-3000 • PMMA PM-1: Polymethyl methacrylate, manufactured by Kuraray Co., Ltd., model Parapet HR

[0034] [Table 1]

[0035] [Table 2]

[0036] [Table 3]

[0037] 2. Manufacturing of resin needles The resin needles 1 of the examples and comparative examples were manufactured in the shapes shown in Figures 1 and 2 using the method described below. The resin needle 1 comprises a puncture portion 10 for puncturing living tissue and a holder 20. The holder 20 comprises a main body 21, a pair of arms 22, 22 provided on both sides of the main body 21, and a rod 23 extending towards the base end of the main body 21. Specifically, the holder 20 was shaped to fit the casing of the "Pinnix Light" puncture device manufactured by Lightnix Corporation. The puncture portion 10 was shaped to fit Embodiment 3 of Patent Document 1. Specifically, the total length L is 0.4 mm, the width W is 0.9 mm, the height H is 0.2 mm, the radius of curvature of the tip portion 11 is 3 μm, and the edge angle θ is 18.3°.

[0038] <Examples and comparative examples other than Examples 14 and 15> The resin needles of the examples and comparative examples other than Examples 14 and 15 were manufactured by pre-drying the resin composition obtained by blending the materials shown in Tables 1 to 3 in the proportions shown in Tables 4 to 6 at 80°C for 5 hours, then completely melting it at 220°C (a temperature above the melting point of polylactic acid), injecting it into a mold at 23°C, and cooling it for 10 seconds. The resin needles were not annealed.

[0039] <Examples 14, 15> The resin needles of Examples 14 and 15 were manufactured by pre-drying a resin composition obtained by blending the materials shown in Tables 1 to 3 in the proportions shown in Table 5 at 80°C for 5 hours, then melting it at 220°C, injecting it into a mold at 100°C, holding it for 300 seconds, and then cooling it to 23°C for 10 seconds.

[0040] [Table 4]

[0041] [Table 5]

[0042] [Table 6]

[0043] 3. Measurement of the physical properties of resin needles and resin compositions The physical properties of the resin needle and resin composition were measured using the method described below.

[0044] <Degree of crystallization and crystallization temperature of polylactic acid component in resin needles> Measurement samples were prepared by cutting the resin needles of the examples and comparative examples to approximately 5 mg each. Next, the measurement samples were heated to 300°C under a nitrogen atmosphere at a rate of 10°C / min using a differential scanning calorimetry analyzer (Hitachi High-Tech Science, DSC7000X). The point at which the material becomes rubbery was defined as the glass transition temperature (Tg), the peak of the crystallization peak as the crystallization temperature (Tc), and its crystallization energy (ΔHc). The peak of the crystallization melting peak as the melting point (Tm), and its melting energy (ΔHm) were also measured. The degree of crystallization was calculated using the values ​​of ΔHm and ΔHc in the following equation 1. In equation (1), "93" represents the melting energy of polylactic acid with 100% crystallization (93 mJ / mg), and "WtP" represents the weight ratio of polylactic acid to the total resin composition (weight of PLA / total weight of resin composition). Note that ΔHm and ΔHc derived from PLA were used in the calculation. It is preferable to determine the Tc and Tm derived from PLA beforehand, for example, by measuring only PLA. Furthermore, the output values ​​of ΔHm and ΔHc are output as energy per unit weight of the entire measurement sample, and are calculated using the weight including components other than PLA. Therefore, in order to calculate the degree of crystallinity of the PLA component in the measurement sample, it is necessary to divide (ΔHm - ΔHc) by WtP. (Formula 1) Crystallinity (%) = [{(ΔHm-ΔHc) / WtP} / 93}]×100

[0045] <Module of elasticity at 80°C> The resin compositions of the examples and comparative examples were extruded at a melting temperature of 220°C to produce a length of 50 mm and a cross-sectional area of ​​3 mm². 2The strand was preheated in an 80°C environment for 5 minutes, and the elastic modulus obtained by measuring the elastic modulus at a tensile speed of 1 mm / min was defined as the 80°C elastic modulus.

[0046] <23℃ growth rate> The resin compositions of the examples and comparative examples were extruded at a melting temperature of 220°C to produce a length of 50 mm and a cross-sectional area of ​​3 mm². 2 The elongation obtained by measuring the elongation of the strand by tensile testing at 1 mm / min in a 23°C environment was defined as the 23°C elongation.

[0047] 4. Evaluation The examples and comparative examples were evaluated using the method described below. The resin needles of the examples yielded good results for all evaluation items. On the other hand, the resin needles of the comparative examples yielded poor results for at least one evaluation item.

[0048] <Fine moldability> The fine moldability of the resin needles in the examples and comparative examples was evaluated based on the presence or absence of shape defects observed visually, according to the following criteria. ◎: Fine details such as the needle tip are molded to the specified shape, and there are no problems with release from the mold. ○: While details such as the needle tip are molded to the specified shape, the adhesion to the mold is somewhat strong, resulting in slightly poor release properties. However, this does not pose a major problem in practical use. △: Although the needle tip and other fine details are molded to the specified shape, the strong adhesion to the mold may occasionally cause damage during demolding, but the product is still usable. ×: The needle tip and other details are not molded to the specified shape, making it unusable.

[0049] <Punctureability before heating / Punctureability after heating> A laminate was prepared by layering a 1.0 mm thick silicone rubber with a rubber hardness of 50, an 8 μm thick aluminum foil, and a 1.5 mm thick silicone rubber with a rubber hardness of 50 in that order. Next, the resin needles of the examples and comparative examples were set inside the casing of a "Pinnix Light manufactured by Lightnix Co., Ltd." and the Pinnix Light was pressed against the 1.0 mm silicone rubber side of the laminate to evaluate the pre-heat puncture capability according to the following criteria, based on whether puncture was possible. Furthermore, the resin needles of the examples and comparative examples were left to stand at 80°C for one week, and the same test was performed to evaluate the post-heat puncture capability according to the following criteria. ◎: Allows for punctures of 1.0 mm or more, and no deformation of the needle is observed. ○: Although slight deformation of the needle is observed, punctures of 1.0 mm or more are possible, and there are absolutely no problems in practical use. △: Significant needle deformation is observed, but punctures of 1.0 mm or more are possible, and the needle is usable. ×: Unable to perform punctures of 1.0 mm or more, making it unusable in practice. [Explanation of Symbols]

[0050] 1: Resin needle 10: Puncture site 11:Tip 20: Holding body 21: Main unit 22: Arm 23: Rod H: Height W: Width L: Total length θ: Edge angle

Claims

1. A resin needle made of a resin composition, The aforementioned resin composition comprises polylactic acid and non-fibrous inorganic particles. The polylactic acid has a weight-average molecular weight of 20,000 to 400,000, and a D-isomer ratio of 15% by mass or less, or 85% by mass or more. The non-fibrous inorganic particles have an average particle size of 0.05 to 20 μm. The resin needle contains 5 to 70 parts by mass of the non-fibrous inorganic particles per 100 parts by mass of the polylactic acid.

2. A resin needle according to claim 1, The resin composition includes a biocompatible resin other than polylactic acid, A resin needle in which the biocompatible resin content is 50 parts by mass or less per 100 parts by mass of polylactic acid.

3. A resin needle according to claim 1, A resin needle having a degree of crystallinity of the polylactic acid component of the resin needle of 1 to 60%.

4. A resin needle according to claim 1, A resin needle in which the crystallization temperature of the polylactic acid component of the resin needle is above 80°C.

5. A resin needle according to claim 1, The resin composition was extruded at a melting temperature of 220°C to produce a length of 50 mm and a cross-sectional area of ​​3 mm². ２ A resin needle in which the strand is preheated in an 80°C environment for 5 minutes and subjected to a tensile test at 1 mm / min, the 80°C modulus of elasticity measured is 10 MPa or higher.

6. A resin needle according to claim 1, The resin composition was extruded at a melting temperature of 220°C to produce a length of 50 mm and a cross-sectional area of ​​3 mm². ２ A resin needle in which the strand is subjected to a tensile test at 1 mm / min in a 23°C environment, and the 23°C elongation is measured to be 1% or more.

7. A resin needle according to claim 1, A resin needle in which the non-fibrous inorganic particles are layered minerals.

8. A resin needle according to claim 7, A resin needle in which the aforementioned layered mineral is talc.

9. A resin needle according to any one of claims 1 to 8, The aforementioned resin needle is a medical needle.

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