Resin composition and crosslinked product

Abstract

Provided are: a resin composition including a polyoctenamer having the structure represented by formula (1), and an organic natural filler; and a crosslinked product thereof.

Description

Resin compositions and crosslinked materials

[0001] This disclosure relates to resin compositions and crosslinked materials.

[0002] Various polymer materials with shape memory properties are known. Shape memory properties refer to the ability to be elastically deformed in a fixed state under specific temperature, pressure, and stress, and then, when heat, electricity, or physical stimulation is applied, the elastic deformation is almost completely relieved, and the material can return to its state before elastic deformation. Examples of polymer materials with shape memory properties include polyurethanes and crosslinked polyethylene. Reference 1 discloses a resin material containing transpolyoctenomer. Reference 2 discloses a shape memory polymer containing chemically crosslinked polycyclooctene.

[0003] Japanese Patent Application Laid-Open No. 63-145325 Special Publication No. 2006-503171

[0004] On the other hand, the inventors recognized that in recent years there has been a demand for alternatives to natural materials such as wood. In addition, the inventors recognized that no polymer material possessing the texture of natural materials while also having shape memory properties had been proposed to date.

[0005] The object of this disclosure is to provide a crosslinked material that has the texture of a natural product while possessing excellent shape memory properties, and a resin composition for obtaining the crosslinked material.

[0006] This disclosure relates to the following: [1] A resin composition comprising a polyoctenomer having a structure represented by the following formula (1) and an organic natural product filler. [2] A crosslinked body, wherein the crosslinked body is a crosslinked body of a resin composition comprising a polyoctenomer and an organic natural product-based filler, and the polyoctenomer has a structure represented by the following formula (1). [3] In the differential scanning calorimetry of the crosslinked body, the differential scanning calorimetry is performed in the order of a first heating process, a cooling process, and a second heating process, and the amount of heat generated from the polyoctenomer in the crosslinked body during the cooling process is ΔH Ｔｃ(mJ / mg) is used to represent the amount of heat absorbed by the polyoctenomer in the crosslinked material during the second heating process, and ΔH is used to represent the amount of heat absorbed by the polyoctenomer in the crosslinked material during the second heating process. ２ｎｄＴｍ When (mJ / mg), ΔH ２ｎｄＴｍ / ΔH Ｔｃ [2] The crosslinked body according to [2], wherein the value of is 0.800 or more. [4] The crosslinked body according to [2] or [3], wherein the resin composition is irradiated with an electron beam or radiation. [5] The crosslinked body according to any one of [2] to [4], wherein the crosslinked body is irradiated with an electron beam, wherein the dose of the electron beam is 100 to 900 kGy. [6] The crosslinked body according to any one of [2] to [5], wherein the glass transition temperature is 0.0°C or less. [7] The crosslinked body according to any one of [2] to [6], wherein the melting point is 30.0 to 65.0°C. [8] The crosslinked body according to any one of [2] to [7], wherein when the melting point of the polyoctenomer is Tm1 (°C) and the melting point of the crosslinked body is Tm2 (°C), Tm2 / Tm1 is 0.80 to 1.00. [9] The crosslinked body according to any one of [2] to [8], wherein the crosslinked body is a shape memory polymer.

[0007] According to this disclosure, a crosslinked material having the texture of a natural product while possessing excellent shape memory properties, and a resin composition for obtaining the crosslinked material are provided.

[0008] The following describes specific embodiments of this disclosure, but each configuration and combination thereof in each embodiment is merely an example, and additions, omissions, substitutions, and other modifications are possible as appropriate, without departing from the spirit of this disclosure. This disclosure is not limited by the embodiments. Furthermore, each aspect disclosed herein can be combined with any other features disclosed herein.

[0009] In this disclosure, "X to Y" indicating a range means "X or greater and Y or less". Furthermore, when numerical ranges expressed as "X to Y" or "X or greater and Y or less" are described in steps (for example, in preferred order), the upper and lower limits of each numerical range can be any combination.

[0010] In the present disclosure, a description such as "one or more selected from the group consisting of X, Y, and Z" means any one of X, Y, Z, a combination of X and Y, a combination of X and Z, a combination of Y and Z, or a combination of X, Y, and Z. Note that when X is a group, a plurality may be selected from X, and the same applies to Y and Z.

[0011] In the present disclosure, a description such as "X such as x1, x2, and x3" gives examples of X as x1, x2, and x3, etc., and does not mean that X is limited to x1, x2, and x3, etc.

[0012] The resin composition of the present disclosure contains a polyoctenamer and an organic natural filler. The polyoctenamer is a polymer having a structure corresponding to octenylene. Examples of the structure corresponding to octenylene include the structure represented by the following formula (1) and the structure represented by the following formula (2). The structure represented by the following formula (1) is a trans-type octenylene structure. Also, the structure represented by the following formula (2) is a cis-type octenylene structure. For example, the polyoctenamer may be a ring-opening polymer of cyclooctene. The polyoctenamer may have a linear structure or a cyclic structure.

[0013] The polyoctenamer has the structure represented by the above formula (1). By having the structure represented by the above formula (1), the melting point and crystallinity of the resulting crosslinked product are likely to be high. The content of the structure represented by the above formula (1) in the polyoctenamer is not particularly limited, but may be 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. The upper limit of the content of the structure represented by the above formula (1) in the polyoctenamer is not particularly limited, and the range of the content may be 50 to 95% by mass, preferably 60 to 95% by mass, more preferably 70 to 85% by mass, and particularly preferably 80 to 85% by mass. Within the above range, it is easy to exhibit shape memory characteristics.

[0014] The polyoctenomer may have the structure shown in formula (2) above. Furthermore, it is preferable that the polyoctenomer consists of the structure shown in formula (1) and the structure shown in formula (2) above. The content of the structure shown in formula (2) in the polyoctenomer is not particularly limited, but may be 5 to 50% by mass, preferably 5 to 40% by mass, more preferably 15 to 30% by mass, and even more preferably 15 to 20% by mass.

[0015] The content of the structure represented by formula (1) in the polyoctenomer is preferably 300 to 500 parts by mass, more preferably 350 to 450 parts by mass, and even more preferably 375 to 425 parts by mass, relative to the content of the structure represented by formula (2) per 100 parts by mass. Within this range, the melting point and crystallinity of the resulting crosslinked material tend to be higher. The content of the structure represented by formula (1) in the polyoctenomer is measured by infrared spectroscopy.

[0016] The melting point of the polyoctenomer is not particularly limited, but is preferably 50.0 to 59.0°C, and more preferably 53.0 to 57.0°C. Within this range, it is possible to keep the processing temperature low when mixing with organic natural product fillers, thereby suppressing deterioration and discoloration of the organic natural product fillers. Furthermore, in the crosslinked material, shape memory properties are more easily and stably exhibited in a room temperature environment (25°C environment). Increasing the content of trans-type polyoctenylene structures in the polyoctenomer increases the melting point. Similarly, decreasing the content of trans-type polyoctenylene structures lowers the melting point. The melting point of the polyoctenomer is measured by differential scanning calorimetry. Specifically, as will be described later, in this disclosure, the melting point Tm in the second heating process is used. ２ｎｄ This is called the melting point Tm1 of polyoctenamer.

[0017] The tensile modulus of polyoctenomer is not particularly limited, but is preferably 80 to 400 MPa, more preferably 100 to 200 MPa, and even more preferably 150 to 180 MPa. Within this range, the shape memory properties of the resulting crosslinked material tend to be superior, and the resulting crosslinked material can deform at room temperature with an appropriate force. Therefore, the crosslinked material can be easily used as a shape memory material in various applications. The tensile modulus of polyoctenomer can be increased by increasing the content of trans-type polyoctenylene structures in the polyoctenomer. Similarly, the tensile modulus can be decreased by decreasing the content of trans-type polyoctenylene structures.

[0018] The tensile modulus of polyoctenamer can be obtained by obtaining an ISO standard test specimen from polyoctenamer and measuring it in accordance with ISO 0527. Specifically, the following conditions are used: • Measurement environment: Temperature 23°C, humidity 50% • Test specimen shape: ISO standard test specimen, distance between chucks 115 mm • Distance gauge gauge marks 50 mm • Tensile speed: 1 mm / min An extensometer is used to measure the displacement.

[0019] As the polyoctenomer, a commercially available product may be used, or it may be synthesized by a known method. An example of a commercially available product is VESTENAMER® 8012 (manufactured by Polypla Evonik). In other words, the polyoctenomer is preferably VESTENAMER® 8012.

[0020] The resin composition of this disclosure contains an organic natural product-based filler. By including an organic natural product-based filler, a natural texture can be obtained. In this disclosure, texture refers to a sensation perceived by a person. That is, by including an organic natural product-based filler, a sensation similar to that of a natural product corresponding to the organic natural product-based filler can be obtained. Examples of sensations include sight, touch, and smell. For example, if the organic natural product-based filler is wood powder, a woody texture such as appearance and smell derived from wood powder will be expressed. An organic natural product-based filler is a filler made from natural materials among organic fillers. Preferably, the organic natural product-based filler is a plant-derived filler. A plant-derived filler is a filler made from plants.

[0021] Organic natural product fillers are not limited to the following, but examples include wood powder such as cedar wood powder and cypress wood powder, wood pellets, pulp, bagasse, kenaf, sawdust, wood fibers, rice hulls, crushed chips, fruit hull powder, waste paper, bamboo powder, beer lees, coffee grounds, crushed nonwoven fabric, cotton, twisted cotton yarn, rayon fibers, paper powder, starch, rice flour, wheat flour, etc. These may be used individually or in combination of two or more. Organic natural product fillers can be appropriately selected depending on the application, but from the viewpoint of the mechanical strength and secondary processability of the resin composition of this disclosure, one or more powders selected from the group consisting of wood powder and bamboo powder are preferred.

[0022] The organic natural product-based filler is subjected to dry or wet grinding as needed, and further sieved as needed. The median diameter (D50 diameter) of the organic natural product-based filler is not particularly limited, but is preferably 0.05 to 10 mm, more preferably 0.1 to 1 mm, even more preferably 0.1 to 0.5 mm, and particularly preferably 0.1 to 0.3 mm. Having the median diameter of the organic natural product-based filler within the above range prevents powdering during handling and reduces the effort and cost of grinding and sieving. In addition, the mechanical strength of the resin composition and its molded articles according to this disclosure tends to be practically sufficient. The method for adjusting the median diameter of the organic natural product-based filler is not particularly limited and can be adjusted, for example, by changing the grinding conditions or by classification. For example, when using a 178 μm mesh-passed organic natural product-based filler, the median diameter falls within the above range. The median diameter of organic natural product fillers can be measured by performing a sieving test based on the method described in JIS Z 8815 General Rules for Sieving Test Methods, creating a particle size distribution diagram showing the test results, and reading the value at the bottom 50% of the cumulative sieve from the resulting diagram.

[0023] The organic natural product filler may be particulate, flattened, irregularly shaped, or a mixture thereof.

[0024] The content of organic natural fillers is not particularly limited, but is preferably 5 to 80% by mass, more preferably 5 to 65% by mass, and even more preferably 5 to 55% by mass. A content of 5% by mass or more of organic natural fillers is preferable because it makes it easier to express the texture derived from the organic natural fillers. For example, if the organic natural filler is wood powder, a woody texture will be expressed, which is preferable. Furthermore, a content of 80% by mass or less makes it easier to manufacture the resin composition containing organic natural fillers, and at the same time, the moldability of this resin composition is also good. As described above, the above range is preferable in terms of the balance between texture and productivity / moldability.

[0025] A resin composition containing a polyoctenomer and an organic natural product-based filler may contain other materials, provided that the resulting crosslinked body has shape memory properties. For example, if the content of the structure represented by formula (1) in the polyoctenomer constituting the resin composition is 50% by mass or more, the other material may be a second polyoctenomer. The second polyoctenomer has the structure represented by formula (1), and the content of the structure represented by formula (1) in the second polyoctenomer is less than 50% by mass. The lower limit of the content of the structure represented by formula (1) in the second polyoctenomer is not particularly limited, and the content may be between 5% by mass and less than 50% by mass, or between 10% and 40% by mass.

[0026] Other materials include polyolefins. The polyolefin is not particularly limited, and known polyolefins such as polyethylene and polypropylene can be used. The total content of other materials in the resin composition containing polyoctenomer and organic natural product filler is not particularly limited, and may be 50.0% by mass or less, preferably 30.0% by mass or less, and more preferably 20.0% by mass or less. The lower limit of the total content of other materials is not particularly limited, and the range of the total content may be 1.0 to 50.0% by mass, 5.0 to 30.0% by mass, or 10.0 to 20.0% by mass.

[0027] Next, the crosslinked body in this disclosure will be described.

[0028] The crosslinked material of this disclosure is a crosslinked material of the above-mentioned resin composition. That is, the crosslinked material of this disclosure is a crosslinked material of a resin composition containing a polyoctenomer and an organic natural product-based filler. The polyoctenomer has the structure shown in formula (1) above. The above-mentioned crosslinked material has the texture of a natural product while possessing excellent shape memory properties. That is, the crosslinked material of this disclosure may be a shape memory polymer. It is believed that the crosslinked material of this disclosure can maintain its deformed state because crystallization occurs due to the orientation of molecules during deformation.

[0029] It is preferable that the crosslinked material does not contain organic peroxides. The absence of organic peroxides in the crosslinked material means that organic peroxides were not used as a means of crosslinking when obtaining the crosslinked material from the resin composition. For example, if pyrolysis gas chromatography analysis of the crosslinked material does not detect any structures corresponding to organic peroxides, it can be said that the crosslinked material does not contain organic peroxides. Methods for obtaining the crosslinked material from the resin composition will be described later.

[0030] Examples of organic peroxides include aromatic organic peroxides such as dicumyl peroxide, tert-butylcumyl peroxide, and benzoyl peroxide, and aliphatic organic peroxides such as di-tert-butyl peroxide and di(tert-butylperoxy)cyclohexane.

[0031] The crosslinked material is preferably a crosslinked material obtained by irradiating a resin composition with an electron beam or radiation, and more preferably a crosslinked material obtained by electron beam irradiation. With such a crosslinked material, it is easier to ensure that the crosslinked material does not contain organic peroxides. Furthermore, in the case of crosslinking containing organic peroxides, it is necessary to raise the temperature to 160°C or higher for crosslinking, which may cause deterioration or discoloration of organic natural product-based fillers. In contrast, a crosslinked material obtained by electron beam or radiation irradiation can suppress deterioration or discoloration of organic natural product-based fillers, making it preferable. Electron beam irradiation and radiation irradiation can be performed using known electron beam irradiation devices or radiation irradiation devices.

[0032] When the crosslinked material is a crosslinked material formed by irradiation with an electron beam, the electron beam dose is preferably 100 to 900 kGy. More preferably, the electron beam dose is 150 kGy or more, and even more preferably 200 kGy or more. By setting the dose within the above range, it becomes easier to obtain excellent shape memory properties. More preferably, the electron beam dose is 850 kGy or less, even more preferably 800 kGy or less, and particularly preferably 400 kGy or less. The electron beam dose may be, for example, 100 to 850 kGy, 150 to 800 kGy, or 200 to 400 kGy. Within the above range, the degree of crosslinking of the crosslinked material tends to be favorable.

[0033] If the crosslinked material is a crosslinked material formed by irradiation with radiation, the radiation dose is preferably 50 to 110 kGy.

[0034] The glass transition temperature of the crosslinked material is not particularly limited, but may be 5.0°C or lower, preferably 0.0°C or lower, and more preferably -5.0°C or lower. Within this range, it is easier to stably exhibit shape memory properties in a room temperature environment. The lower limit of the glass transition temperature is not particularly limited, and the glass transition temperature may be, for example, -70.0 to 5.0°C, -70.0 to 0.0°C, or -70.0 to -5.0°C. The glass transition temperature of the crosslinked material can be changed, for example, by adjusting the degree of crosslinking of the resin composition when obtaining the crosslinked material from the resin composition. Specifically, increasing the dose of electron beams or radiation increases the crosslinking density. As a result, the glass transition temperature increases. Decreasing the dose of electron beams or radiation decreases the crosslinking density. As a result, the glass transition temperature decreases. The glass transition temperature of the crosslinked material is defined as the peak top temperature of tanδ when the crosslinked material is measured using dynamic viscoelasticity measurement (DMA measurement).

[0035] The melting point of the crosslinked material is not particularly limited, but is preferably 30.0 to 65.0°C, more preferably 30.0 to 60.0°C, even more preferably 35.0 to 60.0°C, even more preferably 40.0 to 60.0°C, particularly preferably 45.0 to 60.0°C, and especially preferably 45.0 to 55.0°C. Within this range, the material is more likely to exhibit stable shape memory properties in a room temperature environment. By raising the temperature above the melting point of the crosslinked material, the crystallization caused by molecular orientation melts, and the deformed state is no longer maintained. The melting point of the crosslinked material can be changed, for example, by changing the type of polyoctenomer used in the resin composition. The melting point of the crosslinked material is measured by differential scanning calorimetry. Specifically, as will be described later, in this disclosure, the melting point Tm in the second heating process is used. ２ｎｄ This is called the melting point Tm2 of the bridged structure.

[0036] When the melting point of the resin composition is Tm1 (°C) and the melting point of the crosslinked product is Tm2 (°C), it is preferable that Tm2 / Tm1 is 0.80 to 1.00, more preferably 0.80 to 0.90, and even more preferably 0.85 to 0.90. When it is within this range, it becomes easier to stably exhibit the shape memory property in a normal temperature environment.

[0037] In the differential scanning calorimetry of the crosslinked product, the differential scanning calorimetry is a measurement performed in this order: the first heating process, the cooling process, and the second heating process. The heat generation amount derived from the polyoctenamer in the crosslinked product during the cooling process is ΔH Ｔｃ (mJ / mg), and when the heat absorption amount derived from the polyoctenamer in the crosslinked product during the second heating process is ΔH ２ｎｄＴｍ (mJ / mg), the value of ΔH ２ｎｄＴｍ / ΔH Ｔｃ is preferably 0.800 or more. Here, the heat generation amount ΔH Ｔｃ (mJ / mg) derived from the polyoctenamer in the crosslinked product during the cooling process is the value obtained by dividing the heat generation amount ΔH Ｔｃ０ derived from the crosslinked product during the cooling process obtained in the differential scanning calorimetry by the polyoctenamer ratio in the resin composition (that is, the value converted per 100% by mass of the polyoctenamer). Here, the heat absorption amount ΔH ２ｎｄＴｍ (mJ / mg) derived from the polyoctenamer in the crosslinked product during the second heating process is the value obtained by dividing the heat absorption amount ΔH ２ｎｄＴｍ０ derived from the crosslinked product during the second heating process obtained in the differential scanning calorimetry by the polyoctenamer ratio in the resin composition (that is, the value converted per 100% by mass of the polyoctenamer).

[0038] When the differential scanning calorimetry is a measurement performed in this order: the first heating process, the cooling process, and the second heating process, the crosslinked product melts by the first heating process. The temperature at this time is the melting point Tm １ｓｔ of the crosslinked product in the first heating process. Then, by the subsequent cooling process, the melted crosslinked product crystallizes. The temperature at this time is the crystallization temperature Tc of the crosslinked product, and the heat generation amount at this time is the heat generation amount ΔH Ｔｃ０(mJ / mg). Since the crosslinked material contains organic natural product fillers, the value obtained by converting this calorific value to the amount of heat generated per 100% by mass of polyoctenomer is the calorific value ΔH derived from the polyoctenomer in the crosslinked material during the cooling process. Ｔｃ (mJ / mg) is used. Subsequently, in the second heating process, the crystallized crosslinked material melts. The temperature at this time is the melting point Tm in the second heating process. ２ｎｄ (The melting point Tm2 of the bridged material) is given by this value, and the amount of heat absorbed at this point is the amount of heat absorbed by the bridged material ΔH during the second heating process. ２ｎｄＴｍ０ (mJ / mg). Since the crosslinked material contains organic natural product fillers, this amount of endothermic energy is converted to the amount of endothermic energy ΔH derived from the polyoctenomer in the crosslinked material during the second heating process. ２ｎｄＴｍ Let (mJ / mg). Here, ΔH ２ｎｄＴｍ / ΔH Ｔｃ The value of represents the ratio of the heat of fusion of the crystal obtained by crystallization to the amount of heat released during crystallization. That is, ΔH ２ｎｄＴｍ / ΔH Ｔｃ A value within the above range indicates that the crystalline state of the resin composition before crosslinking is maintained in the crosslinked product. In other words, the molecules can smoothly repeat crystallization and melting. As a result, the shape memory properties can be stably exhibited in a room temperature environment. The specific measurement method will be described later.

[0039] ΔH ２ｎｄＴｍ / ΔH Ｔｃ The value of ΔH is more preferably 0.850 or greater. ２ｎｄＴｍ / ΔH Ｔｃ There is no particular upper limit to the value of ΔH ２ｎｄＴｍ / ΔH Ｔｃ The value of ΔH may be between 0.800 and 1.200, or between 0.850 and 1.100. ２ｎｄＴｍ / ΔH Ｔｃ The value of can be changed, for example, by adjusting the degree of crosslinking of the resin composition when obtaining a crosslinked resin composition. Specifically, increasing the degree of crosslinking of the crosslinked material increases ΔH ２ｎｄＴｍ / ΔH Ｔｃ When the value of increases, and the degree of crosslinking of the crosslinked material is reduced, ΔH ２ｎｄＴｍ / ΔH ＴｃThe value of becomes smaller.

[0040] The amount of heat generated by polyoctenomer in the crosslinked material during the cooling process ΔH Ｔｃ (mJ / mg) is not particularly limited, but may be 38.0 to 70.0 mJ / mg, preferably 40.0 to 65.0 mJ / mg, and more preferably 45.0 to 60.0 mJ / mg. ΔH Ｔｃ This is an indicator of the ease with which crystals form in the crosslinked material. Therefore, ΔH Ｔｃ When the range is as described above, crystals are likely to form in the crosslinked material.

[0041] The crystallization temperature Tc of the crosslinked material is not particularly limited, but may be between 10.0 and 40.0°C, preferably between 15.0 and 40.0°C, and more preferably between 25.0 and 35.0°C. Furthermore, the crystallization temperature Tc of the crosslinked material is more preferably lower than the melting point Tm2 of the crosslinked material. Moreover, the value of Tm2-Tc is preferably between 10 and 30°C, and more preferably between 15 and 25°C. Within the above range, the crosslinked material tends to become supercooled.

[0042] The amount of heat absorbed by the polyoctenomer in the crosslinked material during the second heating process, ΔH ２ｎｄＴｍ The ΔH is not particularly limited, but may be 30.0 to 65.0 mJ / mg, preferably 40.0 to 60.0 mJ / mg, and more preferably 45.0 to 58.0 mJ / mg. ２ｎｄＴｍ ΔH is an indicator of the amount of crystallinity obtained by the orientation of molecules during deformation. Ｔｃ When the above range is present, the crosslinked material is more likely to retain its deformed shape without needing to be cooled when deformed at room temperature.

[0043] Melting point Tm of the bridged material during the first heating process １ｓｔ The temperature is not particularly limited, but may be 30.0 to 70.0°C, preferably 30.0 to 60.0°C, more preferably 30.0 to 55.0°C, and even more preferably 35.0 to 55.0°C. １ｓｔ When the temperature is within the above range, the shape memory properties are exhibited, and the heating temperature required to restore the material to its state before elastic deformation can be lowered.

[0044] The value of Tm² / Tc is not particularly limited, but may be between 1.000 and 2.500, and preferably between 1.500 and 2.200. Within this range, the molecules can smoothly repeat crystallization and melting.

[0045] The method for manufacturing a crosslinked material is not particularly limited, but examples include the following. The method for manufacturing a crosslinked material preferably includes a crosslinking step in which the resin composition is crosslinked. In the crosslinking step, the resin composition is crosslinked. The method for crosslinking the resin composition is not particularly limited, and known crosslinking methods can be used. For example, a method of irradiating the resin composition with an electron beam or radiation can be used. In the case of irradiating the resin composition with an electron beam, the electron beam dose is preferably 100 to 900 kGy. The electron beam dose is more preferably 150 kGy or more, and even more preferably 200 kGy or more. The electron beam dose is more preferably 850 kGy or less, even more preferably 800 kGy or less, and particularly preferably 400 kGy or less. The electron beam dose may be, for example, 100 to 850 kGy, 150 to 800 kGy, or 200 to 400 kGy.

[0046] The resin composition may be molded before the crosslinking process, or the crosslinked body may be molded after the crosslinking process, but it is preferable to mold the resin composition before the crosslinking process. In other words, it is preferable that the method for manufacturing the crosslinked body includes a molding step in which the resin composition is molded before the crosslinking process. Depending on the degree of crosslinking of the crosslinked body, the viscosity of the crosslinked body may be high, and the moldability may decrease. By pre-molding the resin composition before the crosslinking process to obtain a molded product of the resin composition, and then subjecting the molded product to the crosslinking process, it is possible to impart shape memory properties to a molded product with a desired shape. Known molding methods can be used, such as press molding, extrusion molding, and injection molding.

[0047] The method for producing the resin composition in this disclosure is not limited, and known techniques can be used. For example, a method of supplying the material to a melt mixer and melt-kneading it can be used. Examples of the melt mixer include an extruder, a Banbury mixer, a kneader, and a mixing roll. Examples of the extruder include a single-screw extruder and a twin-screw extruder.

[0048] From the viewpoint of suppressing the decomposition and discoloration of the organic natural product-based filler, the method for producing the resin composition in this disclosure preferably involves a melt-kneading temperature of 60°C to 180°C, more preferably 80°C to 160°C, and even more preferably 100°C to 130°C. When the melt-kneading temperature is above the stated temperature, the polyoctenomer can be made to a viscosity suitable for melt-kneading, improving processability. Furthermore, when the melt-kneading temperature is below the stated temperature, the decomposition and discoloration of the organic natural product-based filler can be suppressed, which is preferable.

[0049] Furthermore, the resin composition in this disclosure can also use powdered polyoctenomer. For example, by molding a mixture of powdered polyoctenomer and an organic natural product-based filler as is to obtain the composition, damage to the organic natural product-based filler during melt kneading can be suppressed. Examples of molding methods in this case include press molding. Polyoctenomer is suitable for processing in powder form because it has a high degree of crystallinity and a low glass transition temperature (Tg). A high degree of crystallinity is preferable because it does not easily aggregate at room temperature and is easy to handle. Also, a low glass transition temperature (Tg) allows for a lower processing temperature, which can suppress damage to the organic natural product-based filler.

[0050] The following details the method for measuring the physical properties of crosslinked materials, etc. <Differential Scanning Calorimetry of Resin Compositions and Crosslinked Materials> A resin composition or crosslinked material is used as a sample. 7.5 mg of the sample is weighed into a measuring cup and differential scanning calorimetry is performed. First, the sample is held at -80°C until the baseline stabilizes. Then, the temperature is increased to 250°C at a heating rate of 10°C / min (first heating process). After heating, the sample is held at 250°C for 1 minute. Then, the sample is cooled to -80°C at a cooling rate of 10°C / min (cooling process). After cooling, the sample is held at -80°C for 1 minute. Then, the temperature is increased to 250°C at a heating rate of 10°C / min (second heating process). From the graph obtained from the above measurement, the crystallization temperature Tc of the crosslinked material and the amount of heat generated from the crosslinked material during the cooling process ΔH are determined. Ｔｃ０ ΔH, the amount of heat generated from the polyoctenomer in the crosslinked material during the cooling process. Ｔｃ , the melting point Tm of the bridged material during the first heating process １ｓｔ , the melting point Tm of the bridged material during the second heating process ２ｎｄ ΔH, the amount of heat absorbed by the bridged material during the second heating process. ２ｎｄＴｍ０ ΔH, the amount of heat absorbed by the polyoctenomer in the crosslinked material during the second heating process. ２ｎｄＴｍ Determine each of these. The same procedure applies when a resin composition is used as a sample.

[0051] The present disclosure will be described in detail below with reference to the following embodiments. However, the present disclosure is not limited to the embodiments described below.

[0052] The following materials were prepared to create the resin composition of the example.

[0053] (Polyoctenomer) Polyoctenomer (Trade name: VESTENAMER® 8012, manufactured by Polypla Evonik, 80% by mass of the structure represented by formula (1) above in the polyoctenomer, 20% by mass of the structure represented by formula (2) above in the polyoctenomer, specific gravity 0.9, combustion residue 1.2% by mass, tensile modulus 165 MPa)

[0054] (Organic natural fillers) - Cedar wood powder (manufactured by Naka Wood Co., Ltd., 178 μm mesh passable) - Cypress wood powder (manufactured by Naka Wood Co., Ltd., 178 μm mesh passable) - Bamboo powder (manufactured by Naka Wood Co., Ltd., 178 μm mesh passable)

[0055] (Examples 1-4) Resin compositions A1-A4 were obtained by mixing the above materials in the proportions shown in Table 1 below.

[0056] (Comparative Example 1) A resin composition A5 was prepared using only polyoctenomer (product name: VESTENAMER 8012, manufactured by Polypla Evonik) instead of resin compositions A1 to A4.

[0057] (Examples 5-8) The resin compositions obtained above were pressed by a hot press to form a sheet. More specifically, a 40mm square, 50μm thick aluminum foil was placed between two 40cm square, 1mm thick SUS plates, and a brass mold with a 30cm square, 1.0mm thick sheet and a 12cm square, 1.0mm thick space in the center was sandwiched between them, and 14.0g of the resin composition was placed in the center of the mold. Then, it was inserted into a hot press machine heated to 130°C and preheated for 5 minutes. After that, 5.0 × 10 ７ N / m ２ It was pressed under pressure for 15 minutes. After heating, the mold containing the inserted SUS plate, aluminum foil, and resin composition was removed as a single unit and heated in a press machine heated to 25°C to form a 5.0 × 10 ７ N / m ２ The sample was cooled by pressing it under pressure for 10 minutes. After confirming that it had cooled, the whole sample was removed from the press and the sheet-like resin composition was removed from the mold. Then, the obtained sheet was irradiated with an electron beam using an electron beam irradiation device (NHV Corporation, Cockcroft-Walton type) to crosslink the polyoctenomer and obtain crosslinked bodies B1 to B4. At this time, the electron beam dose was set to 200 kGy. The physical properties of the obtained crosslinked bodies B1 to B4 were measured using the method described above. The measurement results are shown in Table 2. In addition, the obtained crosslinked bodies were evaluated using the method described below. The evaluation results are shown in Table 2.

[0058] (Comparative Example 2) Crosslinked material B5 was obtained in the same manner as in Examples 5 to 8, except that resin composition A5 was used instead of resin compositions A1 to A4. The physical properties of the obtained crosslinked material B5 were measured in the same manner as crosslinked materials B1 to B4. The measurement results are shown in Table 2. Furthermore, the obtained crosslinked material B5 was evaluated using the method described below. The evaluation results are shown in Table 2.

[0059] (Evaluation of Shape Memory Properties) The shape memory properties were evaluated using the following procedure. From the obtained sheet-like crosslinked material, strip-shaped test pieces measuring 1.5 cm in width and 12 cm in length were cut from a portion free of defects such as voids and warping. The strip-shaped test pieces were folded 180 degrees along their length in a 60°C environment to create U-shaped test pieces. The amount of shape recovery was evaluated by immersing the folded test pieces in 60°C hot water. The following criteria were used for evaluation: ・Evaluation Criteria A: Shape memory properties were confirmed. That is, the test piece folded 180 degrees returned to its original shape within a range of 0 to 10 degrees. B: Shape memory properties were partially confirmed. That is, the test piece folded 180 degrees returned to its original shape within a range of more than 10 degrees but less than 180 degrees. C: Shape memory properties were not confirmed. That is, the test piece folded 180 degrees did not return to its original shape and maintained its 180-degree folded state, or it deformed into a shape different from its original shape.

[0060] (Evaluation of the texture of natural materials) The texture of natural materials was evaluated using the following procedure. For the sheets prepared in Examples 1 to 4 and the sheets crosslinked in Examples 5 to 8, the color of the sheets was visually checked to see if it was a hue derived from the organic natural material filler. In addition, the presence or absence of an odor derived from the added organic natural material filler was checked for in the obtained sheets. At this time, the following criteria were used for evaluation. Evaluation criteria A: Both the hue and odor were found to be of the nature of the organic natural material filler. B: Only either the hue or the odor was found to be of the nature of the organic natural material filler. C: Neither the hue nor the odor was found to be of the nature of the organic natural material filler.

[0061] <Reference Example 1> The evaluation was carried out in the same manner as in Examples 5 to 8, except that polyoctenomer (product name: VESTENAMER 8012, manufactured by Polypla Evonik) was used instead of crosslinked materials B1 to B4. The evaluation results are shown in Table 2. In the table, Tm1 indicates the melting point of the resin composition before crosslinking, and Tm １ｓｔ This indicates the melting point of the crosslinked material during the first heating process, and Tm ２ｎｄ This indicates the melting point of the bridged material during the second heating process, and ΔH ２ｎｄＴｍ０ This indicates the amount of heat absorbed by the bridged material during the second heating process, and ΔH ２ｎｄＴｍ ΔH represents the amount of endothermic heat derived from the polyoctenomer in the crosslinked material during the second heating process, Tc represents the crystallization temperature of the crosslinked material, and ΔH Ｔｃ０ This indicates the amount of heat generated by the crosslinked material during the cooling process, and ΔH Ｔｃ This indicates the amount of heat generated from the polyoctenomer in the crosslinked material during the cooling process. However, in the column for Reference Example 1, Tm １ｓｔ This indicates the melting point of the polyoctenamer during the first heating process, and Tm ２ｎｄ This indicates the melting point of the polyoctenamer during the second heating process, and ΔH ２ｎｄＴｍ ΔH represents the amount of heat absorbed by the polyoctenomer during the second heating process, Tc represents the crystallization temperature of the polyoctenomer, and ΔH represents the amount of heat absorbed by the polyoctenomer during the second heating process. Ｔｃ This indicates the amount of heat generated by the polyoctenomer during the cooling process. In the column for Comparative Example 2, ΔH ２ｎｄＴｍ This indicates the amount of heat absorbed by the bridged material during the second heating process, and ΔH Ｔｃ This indicates the amount of heat generated by the crosslinked material during the cooling process.

Claims

1. A resin composition comprising a polyoctenomer having the structure shown in the following formula (1) and an organic natural product-based filler.

2. A crosslinked body, wherein the crosslinked body is a crosslinked body of a resin composition containing a polyoctenomer and an organic natural product-based filler, and the polyoctenomer has a structure represented by the following formula (1).

3. In the differential scanning calorimetry of the crosslinked body, the differential scanning calorimetry is performed in the order of a first heating process, a cooling process, and a second heating process, and the amount of heat generated from the polyoctenomer in the crosslinked body during the cooling process is ΔH Ｔｃ (mJ / mg) is used to represent the amount of heat absorbed by the polyoctenomer in the crosslinked material during the second heating process, and ΔH is used to represent the amount of heat absorbed by the polyoctenomer in the crosslinked material during the second heating process. ２ｎｄＴｍ When (mJ / mg), ΔH ２ｎｄＴｍ / ΔH Ｔｃ The crosslinked body according to claim 2, wherein the value of is 0.800 or more.

4. The crosslinked body according to claim 2 or 3, wherein the resin composition is irradiated with an electron beam or radiation.

5. The crosslinked body according to any one of claims 2 to 4, wherein the crosslinked body is a crosslinked body obtained by irradiating the resin composition with an electron beam, and the dose of the electron beam is 100 to 900 kGy.

6. A crosslinked body according to any one of claims 2 to 5, wherein the glass transition temperature is 0.0°C or less.

7. A crosslinked body according to any one of claims 2 to 6, wherein the melting point is 30.0 to 65.0°C.

8. The crosslinked body according to any one of claims 2 to 7, wherein when the melting point of the polyoctenomer is Tm1 (°C) and the melting point of the crosslinked body is Tm2 (°C), Tm2 / Tm1 is 0.80 to 1.

00.

9. A crosslinked body according to any one of claims 2 to 8, wherein the crosslinked body is a shape memory polymer.

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