Foam and product using same

Abstract

The present invention provides a foam formed from a foamed resin composition, comprising: a hydroxyl-terminated hydrogenated styrene block copolymer represented by formula (A-B) n-OH, (B-A) n-OH, A (B-A) n-OH, or B (A-B) n-OH, having a hydroxyl group at an end, where A block includes a styrene monomer unit and B block includes a conjugated diene monomer unit, and a block-terminated hydrogenated styrene block copolymer represented by formula (A-B) n-OH, (B-A) n-OH, A (B-A) n-OH, A (B-A) n-OH, or B (A-B) n-OH. Wherein the hydroxyl-terminated hydrogenated styrene block copolymer comprises from 10 to 60 wt% of styrene monomer units; 40 mol% or more of the conjugated diene monomer units are hydrogenated; the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000; before hydrogenation, the content of 1, 2-vinyl bonds in a conjugated diene monomer unit of the hydroxyl-terminated hydrogenated styrene block copolymer is 5 to 60 mol%.

Description

Technical Field

[0001] The invention provides a foamed body, which is particularly suitable for midsoles of shoes, other forms of sports foam pads or daily necessities. Background Art

[0002] Ethylene copolymers, such as ethylene vinyl acetate (EVA), are widely used to make foam products in footwear applications, and the process involves first incorporating a peroxide initiator and a chemical blowing agent at a temperature of about 120°C or less, then forming in a mold, crosslinking the resin composition, and then foaming at a temperature of about 140°C to 190°C. Ethylene α-olefin copolymers are also used in footwear foam applications. For example, U.S. Pat. No. 5,407,965 discloses a substantially crosslinked linear ethylene copolymer composition for use in foams. US7666918B2 discloses a foamable composition and foam comprising a multi-block ethylene / α-olefin interpolymer having soft blocks and hard blocks. Blends of ethylene copolymers can also be used to prepare lightweight foams with balanced foaming properties.

[0003] Thermoplastic elastomers (TPE), such as thermoplastic polyurethane (TPU), thermoplastic polyetherester elastomer (TPEE) and polyether block amide (PEBA), are another class of materials suitable for preparing lightweight foams, such as footwear foams. TPE properties are similar to thermosetting rubbers, but can be melt processed like thermoplastics. It consists of two phases: a soft phase that provides elastic properties and a hard phase that aggregates to form a physical crosslinked network. The TPE of the selected composition can have an inherent melt strength that allows foaming without crosslinking, and the foam formed has ideal foaming properties. In general, TPE materials, such as thermoplastic polyurethanes, cannot be used to prepare foams in the foaming processes currently used to prepare EVA foams. For example, EP3259306 discloses a process for preparing foamed thermoplastic polyurethane particles, which includes impregnating a physical foaming agent, such as nitrogen, to foam into foamed particles.

[0004] Styrenic block copolymers (SBC) are a type of TPE that is suitable for preparing lightweight foams in known footwear foaming processes. In the preparation of SBC-type foams, peroxide crosslinking agents are required to achieve the melt strength of the foam. The glass transition temperature of SBC is about 100°C. SBC can be processed at temperatures below 120°C using peroxides and chemical blowing agents, while the chemical structure of the soft block, i.e. butadiene and / or isoprene, as well as hydrogenated forms, can be crosslinked with peroxide initiators. Partial hydrogenation is preferred for optimal crosslinking with peroxides. Therefore, styrenic block copolymers, such as partially hydrogenated SEBS, have been used in footwear foams, in particular for modifying ethylene copolymers to obtain improved properties, such as impact resilience.

[0005] Despite the progress made in applying SBC to foaming applications, there is still a need to develop novel SBC compositions to further enhance their wide applicability to foam applications, especially footwear foam applications. For example, U.S. Patent Publication No. 2022 / 0380566 A1 discloses a foam based on a hydrogenated styrene diblock copolymer having improved processing properties, and the foam has high resilience. As a non-polar polymer mainly containing hydrogenated butadiene blocks, hydrogenated SBC-based foams may have low adhesion to other footwear parts using environmental primers and adhesives during the shoemaking process. At the same time, it is also valuable to explore new blended compositions including SBCs, which can provide differentiated foaming properties to meet the diverse needs of footwear foam applications. Summary of the invention

[0006] The main object of the present invention is to provide a hydroxyl terminated hydrogenated styrene block copolymer which is particularly suitable for footwear foam applications in the following aspects.

[0007] The first feature of the present invention is that the hydroxyl-terminated hydrogenated block copolymer in the foam has excellent adhesion to other footwear components. Since the durability of the shoe is directly dependent on the quality of the bonding process of its components, the adhesion of the foam component to other parts of the shoe is of great concern. Soft styrene block copolymers (such as SEBS) are suitable for footwear foam applications, which contain a high proportion of non-polar ethylene-butylene units. Only foam materials based on styrene block copolymers may have problems in terms of adhesion, which limits their scope of application. The hydroxyl-terminated hydrogenated block copolymer achieves excellent adhesion without affecting the performance of the foam material.

[0008] A second feature of the present invention is that the hydroxyl-terminated hydrogenated styrene block copolymer can be blended with other widely used foaming resins, such as ethylene copolymers and polar thermoplastic elastomers. In order to meet the ever-expanding performance requirements of footwear foams, blending different foaming resins of different chemical properties is mainly used to obtain key properties. The hydroxyl-terminated hydrogenated styrene block copolymer provides additional synergy with other foaming resins.

[0009] The third feature of the present invention is that the hydroxyl-terminated hydrogenated styrene block copolymer can react with at least one functional group selected from the group consisting of anhydride, epoxy and isocyanate through its terminal hydroxyl group to improve its compatibility with other polar polymers in the resin composition. This interaction also enhances the dispersion of additives such as fillers, crosslinking aids or functional chain extenders.

[0010] While not wishing to be limited by theory, the present invention is based on the discovery that hydroxyl terminated hydrogenated styrene block copolymers are best suited for achieving the aforementioned objectives of the present invention.

[0011] According to the purpose of the present invention, the present invention provides a hydroxyl-terminated hydrogenated styrene block copolymer, a foam comprising the hydroxyl-terminated hydrogenated styrene block copolymer, a resin composition comprising the hydroxyl-terminated hydrogenated block copolymer and an ethylene copolymer, a foam using the same, and a preparation method thereof, as well as a resin composition comprising the hydroxyl-terminated hydrogenated block copolymer and a polar thermoplastic elastomer, a foam using the same, and a preparation method thereof.

[0012] (1) A foamed body formed by a foaming resin composition, comprising:

[0013] A hydroxyl-terminated hydrogenated styrene block copolymer, wherein the hydroxyl-terminated hydrogenated styrene block copolymer is a linear block copolymer represented by the following formula:

[0014] (AB)n-OH, (BA)n-OH, A(BA)n-OH or B(AB)n-OH,

[0015] wherein n is 1 to 4 and has a hydroxyl group at the end, wherein the A block comprises a styrene monomer unit before hydrogenation, and the B block comprises a conjugated diene monomer unit before hydrogenation;

[0016] The hydroxyl-terminated hydrogenated styrene block copolymer comprises 10 to 60 wt % of the A block; before hydrogenation, the 1,2-vinyl bond content in the conjugated diene monomer unit of the hydroxyl-terminated hydrogenated styrene block copolymer is 5 to 60 mol %; after hydrogenation, 40 mol % or more of the conjugated diene monomer unit is hydrogenated; and the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000.

[0017] (2) A foamed body formed by a foaming resin composition, comprising: (a) the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer, and (b) an ethylene-based copolymer, wherein the weight ratio (a / b) of component (a) to component (b) is 90 / 10 to 10 / 90.

[0018] (3) A foamed body formed by a foaming resin composition, comprising: (a) the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer, and (b) a polar thermoplastic elastomer, wherein the weight ratio (a / b) of component (a) to component (b) is 90 / 10 to 5 / 95.

[0019] (4) An article prepared from the aforementioned foamed body, which is a footwear component. In some embodiments, the footwear component is a midsole.

[0020] (5) A resin composition comprising:

[0021] A hydroxyl-terminated hydrogenated styrene block copolymer, wherein the hydroxyl-terminated hydrogenated styrene block copolymer is a linear block copolymer represented by the following formula:

[0022] (AB)n-OH, (BA)n-OH, A(BA)n-OH or B(AB)n-OH, wherein n is 1 to 4 and has a hydroxyl group at the end, wherein the A block comprises a styrene monomer unit before hydrogenation and the B block comprises a conjugated diene monomer unit before hydrogenation;

[0023] The hydroxyl-terminated hydrogenated styrene block copolymer comprises 10 to 60 wt % of the A block; before hydrogenation, the 1,2-vinyl bond content in the conjugated diene monomer unit of the hydroxyl-terminated hydrogenated styrene block copolymer is 5 to 60 mol %; after hydrogenation, 40 mol % or more of the conjugated diene monomer unit is hydrogenated; and the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000.

[0024] (6) A use of the aforementioned resin composition for preparing a foam.

[0025] It should be noted that, unless otherwise specified, in this specification, when describing a component as having a component, it means that the component may have one or more of the components, and does not mean that the component has only one component.

[0026] In this specification, unless otherwise stated, feature A “or” feature B means the presence of feature A or the presence of feature B. Feature A “and / or” feature B means the presence of feature A, the presence of feature B, or the presence of both features A and B. Feature A “and” feature B means that feature A and feature B exist at the same time. “Include,” “comprising,” “including,” and “having” mean “including but not limited to.”

[0027] In the present invention, unless otherwise stated, "almost", "about" and "approximately" generally refer to an acceptable error in a specified value determined by those skilled in the art, which error depends on the measurement or determination method of the value. In some embodiments, "almost", "about" and "approximately" refer to within 1, 2, 3 or 4 standard deviations. In some embodiments, "almost", "about" and "approximately" mean within ± 20% of a given value or range, within ± 15%, within ± 10%, within ± 9%, within ± 8%, within ± 7%, within ± 6%, within ± 5%, within ± 4%, within ± 3%, within ± 2%, within ± 1%, within ± 0.5%, within ± 0.05% or less. The quantity given here is an approximate quantity, i.e., "almost", "about" and "approximately" are not specified, and "almost", "approximately" and "approximately" can still be implied. In addition, "in the range of a first numerical value to a second numerical value", "from a first numerical value to a second numerical value" etc. refer to that the range includes the first numerical value, the second numerical value, and other numerical values ​​between the first numerical value and the second numerical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other novel features of the present invention will become more apparent from the detailed description taken in conjunction with the accompanying drawings.

[0029] Figure 1 This is a photo of the peeled foam after the peel adhesion test. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0031] Preferred embodiments of the present invention will be described in more detail below.

[0032] The present invention provides a foamed body formed by crosslinking and foaming a resin composition, which includes a hydroxyl-terminated hydrogenated styrene block copolymer. At the same time, the present invention provides a foamed body formed by crosslinking and foaming a resin composition, which includes the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer and a vinyl copolymer. Furthermore, the present invention provides a foamed body formed by foaming a resin composition, which includes the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer and a polar thermoplastic elastomer. The main components used to form the foamed body of the present invention will be described in detail below.

[0033] (A) Hydroxyl-terminated hydrogenated styrene block copolymer

[0034] The hydroxyl-terminated hydrogenated styrene block copolymer of the present invention has a general formula of (AB)n-OH, (BA)n-OH, A(BA)n-OH or B(AB)n-OH, and has a hydroxyl group at its end, wherein the A block includes a vinyl aromatic unit, and the B block includes a conjugated diene monomer unit, wherein the hydroxyl-terminated hydrogenated styrene block copolymer includes 10 to 60 wt% of the A block; the 1,2-vinyl bond content in the conjugated diene monomer unit is 5 to 60 mol% before hydrogenation; after hydrogenation, 40 mol% or more of the conjugated diene units are hydrogenated, and the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000.

[0035] The hydroxyl-terminated hydrogenated styrene block copolymer is prepared by an anionic polymerization process of sequentially polymerizing the A block and the B block, wherein the anionic polymerization process contains a terminal hydroxyl group, and the hydroxyl group is located at the end of the A block or the end of the B block.

[0036] From the perspective of manufacturing footwear foam materials, the hydroxyl-terminated hydrogenated styrene block copolymer of the present invention is preferably a linear diblock copolymer represented by the formula AB-OH or BA-OH. The hydroxyl-terminated hydrogenated styrene diblock copolymer has significantly improved processing performance in the foam production process, which includes the steps of incorporating a free radical initiator and a blowing agent into a foam composition at a temperature of about 120°C or lower, and then injection molding the composition containing the free radical initiator and the blowing agent in a mold, wherein crosslinking and blowing agent reaction in the mold are carried out at a temperature of about 150°C to 180°C. After the mold is opened, the foam is formed.

[0037] The A block of the hydroxyl-terminated hydrogenated styrene block copolymer of the present invention is a polymer block of styrene units before hydrogenation; and the B block is a polymer block of conjugated diene monomer units before hydrogenation, and the conjugated diene monomer units are selected from the group consisting of butadiene units, isoprene units and combinations thereof.

[0038] Optionally, the A block of the hydroxyl-terminated hydrogenated styrene block copolymer of the present invention is a polymer block of a styrene monomer unit and a conjugated diene monomer unit before hydrogenation, wherein the conjugated diene monomer unit is a butadiene unit, an isoprene unit or a combination thereof, and the content of the conjugated diene monomer unit in the A block accounts for 0wt% to 15wt% of the total weight of the A block. Optionally, the A block is a styrene monomer unit, and the B block is a butadiene monomer unit. Optionally, the B block, before hydrogenation, is a polymer block of a conjugated diene monomer unit and a styrene monomer unit, wherein the conjugated diene monomer unit is a butadiene unit, an isoprene unit and a combination thereof, and the content of the styrene monomer unit accounts for 0wt% to 20wt% of the total weight of the B block.

[0039] In some embodiments, the 1,2-vinyl bond content of the butadiene unit before hydrogenation may be 5 to 60 mol%. In one embodiment, the B block is a polymer block of butadiene, wherein the 1,2-vinyl bond content of the butadiene unit before hydrogenation is 5 to 60 mol%. In one embodiment, the A block is a polymer block of styrene units and butadiene units, wherein the 1,2-vinyl bond content of the butadiene unit before hydrogenation is 5 to 60 mol%. In some embodiments, the B block is a polymer block of butadiene units and styrene units, wherein the 1,2-vinyl bond content of the butadiene unit before hydrogenation is 5 to 60 mol%.

[0040] In some embodiments, the 3,4-vinyl bond content of the isoprene unit is 5 to 60 mol% before hydrogenation. In one embodiment, the B block is a polymer block of isoprene, wherein the 3,4-vinyl bond content of the isoprene unit is 5 to 60 mol% before hydrogenation. In one embodiment, the A block is a polymer block of styrene units and isoprene units, wherein the 3,4-vinyl bond content of the isoprene unit is 5 to 60 mol% before hydrogenation.

[0041] In some embodiments, after hydrogenation, 60 to 95 mol % of the conjugated diene monomer units are hydrogenated.

[0042] In some embodiments, the A block is a polymer block of styrene units and conjugated diene monomer units. More specifically, the content of the conjugated diene monomer units in the A block may be greater than about 0 wt % to less than about 15 wt %, for example, 3 wt %, 6 wt %, 9 wt %, 12 wt % and 15 wt %.

[0043] In some embodiments, the B block is a polymer block of butadiene units and styrene units. More specifically, the content of styrene monomer units in the B block may be greater than about 0 wt % to less than about 20 wt %, for example, 5 wt %, 10 wt % and 15 wt %.

[0044] In some embodiments, the number average functionality (f(n)) of the hydroxyl-terminated styrene block copolymer is 0.9 to 1.0. In some embodiments, the molecular weight distribution (MWD) of the hydroxyl-terminated styrene block copolymer is 1.0 to 1.05.

[0045] The preparation method of the hydroxyl-terminated styrene block copolymer before hydrogenation is not particularly limited, and any known method can be used. In the polymerization method, living anionic polymerization can be used, which is carried out in a hydrocarbon solvent and initiated by an organic alkali metal compound. For example, U.S. Patent No. 3,823,203 clearly describes the above polymer synthesis steps. The hydrocarbon solvent is not particularly limited, and a known solvent can be used. For example, the hydrocarbon solvent can include aliphatic hydrocarbons, such as n-hexane; alicyclic hydrocarbons, such as cyclohexane; aromatic hydrocarbons, such as xylene. The above hydrocarbon solvents can be used alone or in combination of two or more.

[0046] The initiator is not particularly limited, and any known initiator having anionic polymerization activity with vinyl aromatic monomers (e.g., styrene) and conjugated diene monomers (e.g., butadiene) can be used, for example, aliphatic hydrocarbon alkali metal compounds, aromatic hydrocarbon alkali metal compounds, and organic amino alkali metal compounds. The alkali metal used as the initiator may include lithium, sodium, and potassium. In some embodiments, the initiator may be an aliphatic hydrocarbon alkali metal, such as n-butyl lithium.

[0047] The polymerization process for preparing the hydroxyl-terminated styrene block copolymer can be similar to the process used for anionic polymerization. The polymerization can be carried out at a temperature of about 0°C to about 180°C, preferably about 30°C to about 150°C, and most preferably about 30°C to about 90°C. It is carried out in an inert atmosphere (preferably nitrogen) and can also be completed at a pressure in the range of about 0.5 bar to about 10 bar. The polymerization process generally takes less than 12 hours, depending on the temperature, the concentration of the monomer components, the molecular weight of the polymer, etc.

[0048] The above-mentioned chain end functionalization method is clearly described in U.S. Patent No. 5,693,711. For example, a styrene triblock copolymer with hydroxyl groups at the end can be prepared as follows. First, styrene is introduced to produce styrene blocks, and then butadiene is introduced to form a middle block. Next, styrene is introduced again to form end blocks. In the third step, an alkylene oxide, such as ethylene oxide or propylene oxide, is introduced as an end-capping agent to form hydroxyl groups at the end. A compound with active hydrogen, such as an alcohol, a carboxylic acid or water is then added to terminate the polymerization process. In some embodiments, the alkylene oxide is selected from one or more of ethylene oxide, propylene oxide, 1,2-butylene oxide and 1,2-pentene oxide. It is preferred to use ethylene oxide as an end-capping agent to form hydroxyl groups.

[0049] Hydrogenation of the hydroxyl-terminated styrene block copolymer having hydroxyl groups at the end can be similar to known hydrogenation processes. For example, hydrogenation can be carried out using methods such as those described in U.S. Pat. Nos. 3,595,942 and 3,700,633. The hydrogenation method will use a suitable catalyst. The catalyst mentioned here can include a Group VIII metal, such as nickel or cobalt, which is combined with a suitable reducing agent (e.g., an alkyl aluminum or hydride of a metal selected from Groups IA, II-A and III-A of the Periodic Table of the Elements (particularly lithium, magnesium or aluminum)).

[0050] The hydrogenation process is not particularly limited, but the hydrogenation is usually carried out at a temperature of 0° C. to 180° C., preferably 30° C. to 150° C. The hydrogen pressure in the process is not particularly limited, but is usually 0.1 to 20 MPa, 0.2 to 15 MPa or 0.3 to 5 MPa. The reaction time is usually 1 minute to 10 hours or 10 minutes to 5 hours.

[0051] The hydrogenation process can be a batch process, a continuous process or a combination thereof. If necessary, the residual catalyst can be removed. The hydrogenated polymer can be separated by pouring hot water under stirring, and the organic solvent can be removed by stripping.

[0052] In some embodiments, the microstructure of the conjugated diene segments of the hydrogenated styrene copolymer, for example, the vinyl bond content and styrene content before hydrogenation, and the degree of hydrogenation after hydrogenation, can be determined using proton nuclear magnetic resonance (NMR). 1 In addition, the weight average molecular weight can be determined using gel permeation chromatography (GPC).

[0053] (B) Ethylene copolymer

[0054] In some embodiments of the present invention, the resin composition may include the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer and a vinyl copolymer. In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the vinyl copolymer is 90 / 10 to 10 / 90.

[0055] In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the ethylene copolymer may be 50 / 50 to 10 / 90. In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the ethylene copolymer may be, for example, 50 / 50 to 10 / 90, 40 / 60 to 10 / 90, 35 / 65 to 10 / 90, or 30 / 70 to 10 / 90.

[0056] In the present invention, the ethylene copolymer is not particularly limited, and known ethylene copolymers can be used. For example, a suitable ethylene copolymer can be an ethylene-vinyl acetate copolymer (EVA), which is copolymerized by ethylene and vinyl acetate; an ethylene-α-olefin random copolymer; an olefin block copolymer, including a polymer block of ethylene units and a polymer block of C4-C8 α-olefin units; polyethylene; or a combination thereof. In some embodiments, the polyethylene is a linear low-density polyethylene.

[0057] In some embodiments, the ethylene copolymer may be an ethylene-vinyl acetate copolymer, and the content of vinyl acetate may account for about 15 to 40 wt % of the total weight of the ethylene-vinyl acetate copolymer. In some embodiments, the ethylene copolymer may be an ethylene-α-olefin-based random copolymer, wherein the α-olefin may include 1-butene, 1-pentene, 1-hexene, 1-octene, or a combination thereof, such as TAFMER® olefin copolymer purchased from Mitsui Chemicals and ENGAGE® purchased from Dow Chemical Company. In some embodiments, the ethylene copolymer is an ethylene α-olefin-based random copolymer, which is composed of ethylene units and octene units.

[0058] In some embodiments, the ethylene copolymer may be an olefin block copolymer, such as INFUSE® olefin block copolymer available from Dow Chemical Company. In one embodiment, the ethylene copolymer is an olefin block copolymer, including polymer blocks of ethylene units. In some embodiments, the ethylene copolymer is an olefin block copolymer, including polymer blocks of ethylene units and polymer blocks of octene units. The preferred olefin block copolymer has a melting point of 115° C. to 130° C. and a density of 0.875 g / cc to 0.945 g / cc.

[0059] In some embodiments, the ethylene-based copolymer may further include high-density polyethylene and low-density polyethylene for fine-tuning properties.

[0060] (C) Polar thermoplastic elastomer

[0061] In some embodiments of the present invention, the resin composition for preparing the foam may include the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer and TPU (thermoplastic polyurethane). In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to TPU is 90 / 10 to 10 / 90.

[0062] In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the TPU may be 50 / 50 to 10 / 90. In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the TPU may be, for example, 50 / 50 to 10 / 90, 40 / 60 to 10 / 90, 35 / 65 to 10 / 90, or 30 / 70 to 10 / 90.

[0063] In the present invention, the structure of TPU is not particularly limited, and known copolymers prepared from diisocyanates, chain extenders or short-chain diols and polyols or long-chain diols can be used. It is a block copolymer composed of a soft segment and a hard segment. The hard segment is an isocyanate, which can be divided into aliphatic or aromatic according to the type of isocyanate. The soft segment is made of polyols or long-chain diols. In addition, short-chain diols may exist in the TPU structure as chain extenders.

[0064] In some embodiments of the present invention, the resin composition may include the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer and TPEE (thermoplastic polyester elastomer, also known as thermoplastic copolyester). One of the most famous trade names is Hytrel® manufactured by DuPont™. In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to TPEE is 90 / 10 to 10 / 90.

[0065] In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to TPEE may be 50 / 50 to 5 / 95. In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to TPEE may be, for example, 50 / 50 to 10 / 90, 40 / 60 to 10 / 90, 35 / 65 to 10 / 90, or 30 / 70 to 10 / 90.

[0066] In the present invention, the structure of TPEE is not particularly limited, and it can be a known copolymer containing alternating segments of hard blocks and soft blocks. The hard segments are usually made of polyesters with aromatic rings, which give TPEE strength and heat resistance. The soft segments are usually made of polyethers or polyesters with aliphatic chains, which give the material flexibility and elasticity. In some embodiments, TPEE is a linear block copolymer containing a PBT (polybutylene terephthalate) polyester hard segment (crystalline phase) and an aliphatic polyester or polyether (amorphous phase) soft segment.

[0067] In some embodiments of the present invention, the resin composition may include the aforementioned hydroxyl-terminated hydrogenated styrene block copolymer and PEBA (polyether block amide). One of the most famous trade names is Pebax® manufactured by Arkema. In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to PEBA is 90 / 10 to 10 / 90.

[0068] In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the PEBA may be 50 / 50 to 5 / 95. In some embodiments, the weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the PEBA may be, for example, 50 / 50 to 10 / 90, 40 / 60 to 10 / 90, 35 / 65 to 10 / 90, or 30 / 70 to 10 / 90.

[0069] In the present invention, the structure of PEBA is not particularly limited, and can be a known copolymer containing alternating segments of hard blocks and soft blocks. The hard segments are usually made of polyamide (PA), which gives PEBA strength and heat resistance. The soft segments are usually made of polyether, which gives softness and elasticity.

[0070] In the present invention, the foamed body can be prepared by a process including injection molding the resin composition in an injection mold, wherein the process includes: crosslinking the resin composition using an organic peroxide initiator, and foaming the resin composition using a chemical foaming agent, wherein the crosslinking temperature in the injection molding mold is about 150°C to about 200°C.

[0071] (D) Organic peroxide

[0072] In the present invention, the organic peroxide suitable for the crosslinked resin composition is not particularly limited, and known organic peroxides can be used. For example, dicumyl peroxide (DCP), 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, bis(1-(tert-butylperoxy)-1-methylethyl)-benzene (BIPB) and di-t-butylperoxide are preferred, and are widely used in the preparation of foams. The amount of the organic peroxide is not particularly limited, but is preferably 0.01 to 10 parts, more preferably 0.1 to 3 parts, based on 100 parts by weight of the total amount of the resin composition.

[0073] (E) Chemical foaming agent

[0074] The foaming agent of the present invention is not particularly limited, and any known foaming agent can be used. In some embodiments, the foaming agent can be an organic foaming agent or an inorganic thermal decomposition foaming agent. Among these foaming agents, the most widely known organic foaming agents may include azodicarbonamide (AC), 4,4'-oxybis(benzenesulfonylhydrazide), p-toluenesulfonylsemicarbazide, N,N'-dinitrosopentamethylenetetramine, diphenylsulfone-3,3'-disulfonyl hydrazide (DPSDSH) or trihydraznotriazine; as a specific example of an inorganic thermal decomposition type foaming agent, it may include sodium bicarbonate, ammonium bicarbonate, sodium carbonate or ammonium carbonate. Among the above-mentioned blowing agent types, azodicarbonamide (AC) is most preferred and used in the present invention. The amount of the blowing agent used is not particularly limited, but is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the total weight of the resin composition.

[0075] (F) Other additives

[0076] There is no particular limitation on the additives; however, if necessary, in addition to the aforementioned components, the resin composition for foaming of the present invention may further include a crosslinking aid, a functional chain extender, an organic metal compound, a filler, a heat stabilizer and a weather stabilizer, a pigment, etc. The functional chain extender can be used to crosslink the resin composition, and the functional chain extender includes at least one functional group selected from the group consisting of anhydride, epoxy and isocyanate, which can react with the terminal hydroxyl group of the hydroxyl-terminated hydrogenated styrene block copolymer.

[0077] In order to accelerate the rate of the crosslinking reaction, the present invention can use a crosslinking aid. For example, the crosslinking aid may include triallyl isocyanurate, triallyl cyanurate, ethylene glycol dimethacrylate or vinyl butyrate. In order to make the foam body pores more delicate or more uniform, an organic metal compound can be added to the foam body. For example, preferred organic metal compounds may include zinc diacrylate and zinc dimethacrylate, which can also be used as a crosslinking aid. In order to save costs, adjust hardness or modulus and nucleation, a filler is usually included in the resin composition. Examples of fillers may include clay, silicon dioxide, talc, titanium dioxide, zinc oxide or calcium carbonate.

[0078] In order to improve the durability of foam products, the most common method is to add heat stabilizers and weather stabilizers to the resin composition. Heat stabilizers may include phosphorus-based types, such as Irgafos 168. Weather stabilizers may include hindered phenol-based types, such as pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate]. On the other hand, examples of pigments may include azo pigments, phthalocyanine pigments, oxide pigments, chromate pigments, molybdate pigments, inorganic pigments and carbon black.

[0079] Preparation of foaming resin composition

[0080] The resin composition of this embodiment can be prepared by first melting and kneading the above-mentioned components of the hydroxyl-terminated hydrogenated styrene block copolymer and the ethylene copolymer (or the optional polar thermoplastic elastomer) using a kneader, and then adding an organic peroxide, a foaming agent, and other additives (such as a filler). The above operation is carried out below 120° C. to avoid premature decomposition of the peroxide and the foaming agent.

[0081] The method of melt mixing and blending is not particularly limited, and known methods can be used. For example, extruders such as single screw extruder, twin screw extruder, multi-screw extruder, Henschel mixer, Banbury mixer, roll mill, kneader can be applied to the present invention. In the present embodiment, the melt mixing method using a kneader is preferably used.

[0082] After the melt mixing process, the shape of the resin composition is not particularly limited. For example, it can be formed into a pellet shape, a flake shape, a strand shape, or a chip shape. For example, the components can be mixed by a granulator or the like to form particles. For example, after kneading the components of the resin composition, a roll mill is used to form a sheet to be foamed.

[0083] The polymer structure of the hydroxy-terminated hydrogenated styrene block copolymer was identified as follows.

[0084] Molecular weight and molecular weight distribution

[0085] The weight average molecular weight (Mw) and number average molecular weight (Mn) are measured by gel permeation chromatography (GPC) instrument. The molecular weight values ​​of the peaks in the chromatogram are calculated by the calibration curve of commercially available standard polystyrene. The molecular weight distribution (Mw / Mn) is determined by the weight average molecular weight (Mw) and the number average molecular weight (Mn). More detailed information on the test steps and instrument information is described below. The apparatus is a commercial GPC system provided by Waters, including PDI and refractive index detectors. Tetrahydrofuran (THF) is generally selected as the solvent. The measurement temperature is maintained at 40°C. The flow rate is 1mL / min and the throughput is 100μL. The ratio of hydrogenated block copolymer / THF is 3mg / 15cc.

[0086] Styrene content and vinyl bond content

[0087] Before hydrogenation, the styrene content and vinyl bond content of the hydrogenated styrene diblock copolymer were measured using VARIAN 400 supplied by Agilent Technologies, Inc. 1 H-NMR spectrum is used for determination. Deuterated chloroform is generally selected as the solvent.

[0088] Degree of hydrogenation

[0089] The degree of hydrogenation can be determined according to 1 The calculation formula is as follows:

[0090] Degree of hydrogenation (mol%) = B / (A+B)×100%

[0091] A: Number of moles of unhydrogenated conjugated diene monomer units

[0092] B: Number of moles of hydrogenated conjugated diene monomer units

[0093] Number Average Functionality (f(n))

[0094] The number average functionality of the hydroxyl-terminated hydrogenated styrene block copolymer can be obtained by 1 H-NMR spectrum and GPC.

[0095]

[0096] Where, f(n): number average functionality

[0097] C:

[0098] D: moles of methylene

[0099] E: molar number of styrene monomer units

[0100] Melt flow index

[0101] MFI (melt flow index) is measured according to ASTM-D1238.

[0102] In some embodiments of the present invention, the obtained foam has at least one of the following characteristics: a foaming density of 0.1 to 0.5 g / cm 3 , impact resilience is 50% to 80%, and hardness (Asker C) is 20 to 70.

[0103] The evaluation method of the mechanical properties of the cross-linked foam is as follows.

[0104] Specific gravity

[0105] The primary cross-linked foam was punched out into a circular shape having a diameter of 2.54 cm and a thickness of 1 cm, and measured using an electronic densitometer (MS-204S, manufactured by Mettler Toledo Co., Ltd.).

[0106] hardness

[0107] The hardness (Asker C) of the primary crosslinked foam was measured based on ASTM D2240 using an Asker durometer C hardness tester (Type C, manufactured by Polymer Co., Ltd.), and the value was read within 1 second. In addition, the average value (arithmetic mean) of 5 points was taken as the hardness.

[0108] Split tear strength

[0109] The delamination tear strength of the primary crosslinked foam is measured according to ASTM D3574 F.

[0110] Tensile strength

[0111] The tensile strength at break of the primary cross-linked foam is measured according to ASTM D412.

[0112] Elongation

[0113] The elongation at break of the primary cross-linked foam is measured in accordance with ASTM D412.

[0114] Compression set

[0115] The primary cross-linked foam was punched into a circular shape with a diameter of 2.54 cm as a test piece, and compressed to a thickness of 50%. After being kept at 50°C for 6 hours, the pressure was released and the thickness was measured after 1 hour. The magnitude of the residual deformation was evaluated.

[0116] Impact resilience

[0117] The impact resilience of the cross-linked foam is measured in a vertical rebound device according to ASTM-D2632. The impact resilience refers to the ratio of the rebound height of a metal plunger with a specified mass and shape dropped on a foam sample to the drop height.

[0118] Shrinkage

[0119] The shrinkage of the foam is determined according to ASTM-D1917. The sample is cut into a square specimen with a length of 5 cm and a thickness of 1 cm. First, the original length of the specimen is recorded, and then the specimen is placed in an oven at 70°C / 40 minutes. After heating, the sample is taken out of the oven and cooled at room temperature. After cooling, the length is measured again, and the length change is recorded as the shrinkage.

[0120] Evaluation of Adhesion Properties of Foams Containing Hydroxyl-Terminated Hydrogenated Block Copolymers

[0121] The adhesion of the foam was evaluated by peeling the treated foam and vulcanized samples with the treatment agent and PU adhesive. The components used in the adhesive samples in the test are as follows:

[0122] 1) A foam sample having a thickness of 10 mm in a comparative example without a hydroxyl-terminated block copolymer and an embodiment containing a hydroxyl-terminated block copolymer, as shown in Table 2;

[0123] 2). A vulcanized rubber sheet with a thickness of 2 mm provided by Taiwan Yongshun Enterprise Co., Ltd. is used to bond with the foam sample;

[0124] 3). The treatment agents used in the <treatment agent system> are Greco 001A and 001B, purchased from Datoong Resin Chemical Co., Ltd., Taiwan;

[0125] 4). In the <PU bonding system>, the PU-based adhesive is Greco 6608; the curing agent is Greco 368; both the PU-based adhesive and the curing agent are purchased from Datoong Resin Chemical Co., Ltd. (Taiwan).

[0126] The preparation steps of the bonded sample obtained by bonding the foam sample and the vulcanized rubber sheet with the treatment agent and the PU adhesive are as follows:

[0127] 1). Perform a polishing and cleaning procedure on the foam sample and the vulcanized rubber sheet. Use a grinding machine for polishing to make the surface of the sample reach the required roughness or smoothness. The cleaning process is carried out with ethanol. After the polishing and cleaning treatment, place the sample sheets in an oven at 70 °C for 20 minutes to dry;

[0128] 2). After充分 mixing the aqueous treatment agents Greco 001A and 001B at a weight ratio of 100 / 2, brush the treatment agent solution onto the polished surfaces of the foam sample and the vulcanized rubber sheet. Then place these sample sheets in an oven at 70 °C for 4 minutes to allow the solvent to evaporate;

[0129] 3). The grade of the PU adhesive is 6608, and the grade of the curing agent is 368. Before brushing the adhesive onto the sample, mix the above two materials at a weight ratio of 100 / 5. After充分 mixing the adhesive and the curing agent, brush the mixture onto the surfaces of the foam sample and the vulcanized rubber sheet treated with the treatment agent. Then place these sample sheets in an oven at 70 °C for 4 minutes to allow the solvent to evaporate.

[0130] 4).贴合 the treated surface of the foam sheet to the treated surface of the vulcanized rubber sheet, apply a fixed pressure to the bonded sheet sample for several seconds to bond the foam sample and the vulcanized rubber sheet. After leaving the bonded sheet sample at room temperature for more than 24 hours, finally cut the sheet sample into test samples with a length of 15 cm and a width of 25 mm.

[0131] Refer to ASTM D1876 and use the T-peel test method to evaluate the bonding strength between the foam / vulcanized rubber sheet. Use a tensile testing machine (Instron 3365) to measure the bonding strength, with the unit of kgf / cm.

[0132] Materials for the examples and comparative examples

[0133] Ethylene copolymer

[0134] EVA 659 is an ethylene-vinyl acetate copolymer with a vinyl acetate content of 25 wt % and a melt flow index of 3 g / 10 min measured at 190°C / 2.16 kgf. It is manufactured by Taiwan Polymer Chemicals Co., Ltd. (USI Corporation) under the trade name "UE659".

[0135] OBC 9530 is an olefin block copolymer; specifically, OBC 9530 is an ethylene / 1-octene block copolymer with a melt flow index of 5.0 g / 10 min and a density of 0.887 g / cm2 at 190°C / 2.16 kgf. 3 , melting point 119°C, produced by Dow Chemical Company, trade name "Infuse 9530".

[0136] POE 8450 is an ethylene / 1-octene random copolymer with a melt flow index of 3.0 g / 10 min and a hardness of 0.902 g / cm2 at 190°C / 2.16 kgf. 3 , manufactured by The Dow Chemical Company under the trade name “Engage 8450”.

[0137] Organic peroxide

[0138] Bis(1-(tert-butylperoxy)-1-methylethyl)-benzene (BIPB) manufactured by Arkema Group.

[0139] Chemical foaming agent

[0140] Azodicarbonamide (AC) was manufactured by Kumyang Corporation.

[0141] Other additives

[0142] Calcium carbonate was produced by Yuncheng Chemical Industrial Co., Ltd.; ZnO (zinc oxide) was produced by Diamonchem International Co., Ltd.; stearic acid was produced by Vulchem ​​Inc.

[0143] In some embodiments of the present invention, the obtained foam can be used as a footwear component, for example, a midsole.

[0144] Different embodiments of the present invention are provided in the following description. These embodiments are intended to explain the technical content of the present invention, but do not limit the scope of the present invention. The features described in the embodiments can be applied to other embodiments by appropriate modification, replacement, combination or separation.

[0145] The present invention is described in more detail below by way of examples, but these examples are not intended to limit the scope of the present invention. Unless otherwise stated, in the following preparation examples, embodiments and comparative examples, temperatures are all in degrees Celsius, and parts and percentages are all in weight. The relationship between weight (or mass) parts and volume parts is similar to the relationship between kilograms and liters.

[0146] Hydroxyl terminated hydrogenated block copolymer samples were prepared as follows.

[0147] SEB-OH-A

[0148] SEB-OH-A, a hydroxyl-terminated hydrogenated styrene-butadiene-styrene diblock copolymer, was prepared and identified as follows. First, 4800 g of cyclohexane, 15.7 mmol of n-butyl lithium and 166 mmol of tetrahydrofuran (THF) were charged into a 10 liter reactor equipped with a heater and a stirrer. Secondly, 160 g of styrene was added to the solvent and anionic polymerization was carried out at a temperature of about 50°C. In the third step, 640 g of butadiene was added to the reactor. After the butadiene was completely reacted, 1.2 g of propylene oxide was added to form a hydroxyl-terminated styrene-butadiene diblock copolymer (SB-OH). Methanol was then added to terminate the polymerization. The SB-OH copolymer has a styrene content of 20 wt%, and a 1,2-vinyl bond content of about 38 mol% in the butadiene block.

[0149] The SB-OH copolymer obtained through the above steps is then hydrogenated in a pressure vessel using nickel 2-ethylhexanoate / TEAL catalyst and hydrogen. The temperature of the hydrogenation process is controlled at about 40°C to 100°C. After about 80 mol% of the butadiene block is hydrogenated, the hydrogenation reaction is terminated. Then, the obtained sample is washed with hot acidic water to remove the residual catalyst. Finally, the block copolymer is separated by coagulation in hot water and then dried. The yield of hydroxyl-terminated hydrogenated styrene-butadiene diblock copolymer (SEB-OH) is about 80%.

[0150] According to the analysis results, the hydrogenation rate of the obtained SEB-OH-A copolymer was 79 mol%, the weight average molecular weight was about 75,000, the molecular weight distribution (weight average molecular weight / number average molecular weight) was 1.03, and the MFI measured at 190°C / 5kgf was 0.4.

[0151] SEBS-OH-A

[0152] SEBS-OH-A is a hydroxyl-terminated hydrogenated styrene-butadiene-styrene triblock copolymer, and its preparation and identification methods are described in detail as follows. First, 4800g of cyclohexane, 16.8mmol of n-butyl lithium and 166mmol of tetrahydrofuran (THF) are loaded into a 10-liter reactor equipped with a heater and a stirrer. Secondly, 80g of styrene is added to the solvent and anionic polymerization is carried out at a temperature of about 50°C. In the third step, 640g of butadiene is added to the reactor until the butadiene reacts completely. In the fourth step, 80g of styrene is added to the reactor. After the polymerization of styrene is completed, 1.6g of propylene oxide is added to form a hydroxyl-terminated styrene-butadiene-styrene triblock copolymer (SBS-OH) structure. Methanol is then added to terminate the polymerization. The styrene content of the SBS-OH copolymer is 20wt%, and the 1,2-vinyl bond content in the butadiene block is about 40mol%.

[0153] The SBS-OH copolymer obtained through the above steps is then hydrogenated in a pressure vessel using a nickel 2-ethylhexanoate / TEAL catalyst and hydrogen. The temperature of the hydrogenation step is controlled at about 40°C to 100°C. After about 80 mol% of the butadiene block is hydrogenated, the hydrogenation reaction is terminated. The resulting sample is then washed with hot acidic water to remove the residual catalyst. Finally, the block copolymer is isolated by coagulation in hot water and then dried. The yield of the SEBS-OH copolymer is about 80%.

[0154] According to the analysis results, the hydrogenation degree of the obtained SEBS-OH-A copolymer is 82 mol%, the weight average molecular weight is about 53,000, the molecular weight distribution (weight average molecular weight / number average molecular weight) is 1.03, and the MFI measured at 190°C / 5kgf is 18.

[0155] SEB-OH-B

[0156] SEB-OH-B, a hydroxyl terminated styrene-butadiene diblock copolymer, was prepared and characterized as follows.

[0157] First, 4800g of cyclohexane, 12.6 mmol of n-butyl lithium and 166 mmol of tetrahydrofuran (THF) were loaded into a 10-liter reactor equipped with a heater and agitator. Secondly, 160g of styrene was added to the solvent and anionic polymerization was carried out at a temperature of about 50°C. In the third step, 640g of butadiene was added to the reactor. After the butadiene reaction was complete, 1g of ethylene oxide was added to form a hydroxyl-terminated styrene-butadiene diblock copolymer structure (SB-OH). Methanol was then added to terminate the polymerization. The SB-OH copolymer has a styrene content of 20wt%, and a 1,2-vinyl bond content of about 40mol% in the butadiene block.

[0158] The SB-OH copolymer obtained by the above steps is then hydrogenated in a pressure vessel using nickel 2-ethylhexanoate / TEAL catalyst and hydrogen. The temperature of the hydrogenation process is controlled at about 40°C to 100°C. After about 80 mol% of the butadiene block is hydrogenated, the hydrogenation reaction is terminated. Then, the obtained sample is washed with hot acidic water to remove the residual catalyst. Finally, the block copolymer is separated by coagulation in hot water and then dried. The yield of the SEB-OH copolymer is about 80%.

[0159] According to the analysis results, the hydrogenation degree of the obtained SEB-OH-B copolymer was 85 mol %, the weight average molecular weight was about 64,000, the molecular weight distribution (weight average molecular weight / number average molecular weight) was 1.03, and the f(n) value was about 0.95.

[0160] SEB-OH-C

[0161] SEB-OH-C, a hydroxyl-terminated hydrogenated styrene-butadiene diblock copolymer, is prepared using the same method as SEB-OH-B, and the hydroxyl-terminated hydrogenated styrene-butadiene diblock copolymer is formed by reacting with ethylene oxide, and has a styrene content of 34 wt%, a 1,2-vinyl bond content of the butadiene block of about 41 mol%, and a hydrogenation degree of 82 mol%. The weight average molecular weight is about 55,000, and the molecular weight distribution (weight average molecular weight / number average molecular weight) is 1.03, and the f(n) value is about 0.95.

[0162] SEBS-OH-B

[0163] SEBS-OH-B, a hydroxyl terminated hydrogenated styrene-butadiene-styrene triblock copolymer, was prepared and characterized as follows.

[0164] First, 4800g of cyclohexane, 16.8mmol of n-butyl lithium and 166mmol of tetrahydrofuran (THF) were loaded into a 10-liter reactor equipped with a heater and agitator. Secondly, 120g of styrene was added to the solvent and anionic polymerization was carried out at a temperature of about 50°C. In the third step, 560g of butadiene was added to the reactor until the butadiene reaction was complete. In the fourth step, 120g of styrene was added to the reactor, and when the styrene polymerization was completed, 1.56g of ethylene oxide was added to form a hydroxyl-terminated styrene-butadiene-styrene triblock copolymer (SBS-OH) structure. Methanol was then added to terminate the polymerization. The styrene content of the SBS-OH copolymer was 30wt%, and the 1,2-vinyl bond content in the butadiene block was about 40.1mol%.

[0165] The SBS-OH copolymer obtained by the above steps is then hydrogenated in a pressure vessel using nickel 2-ethylhexanoate / TEAL catalyst and hydrogen. The hydrogenation process temperature is controlled at about 40°C to 100°C. After about 80 mol% of the butadiene block is hydrogenated, the hydrogenation reaction is terminated. Thereafter, the obtained sample is washed with hot acidic water to remove the residual catalyst. Finally, the block copolymer is separated by coagulation in hot water and then dried. The yield of the SEBS-OH copolymer is about 80%.

[0166] According to the analysis results, the hydrogenation rate of the obtained SEBS-OH-B was 85.3 mol %, the weight average molecular weight was about 45,000, the molecular weight distribution (weight average molecular weight / number average molecular weight) was 1.03, and the f(n) value was about 0.95.

[0167] SEBS-OH-C

[0168] SEBS-OH-C is a hydroxyl-terminated hydrogenated styrene-butadiene-styrene triblock copolymer. SEBS-OH-C is prepared using the same preparation method as SEBS-OH-B with hydroxyl termination, which is generated by reaction with ethylene oxide, with a styrene content of 20wt%, a 1,2-vinyl bond content of the butadiene block of about 40mol%, and a hydrogenation degree of 82mol%. The weight average molecular weight is about 53,000, the molecular weight distribution (weight average molecular weight / number average molecular weight) is 1.03, and the f(n) value is about 0.95.

[0169] SEBS-OH-A and SEB-OH-A were prepared into foams as follows.

[0170] SEBS-OH-A foam

[0171] 100 parts of SEBS-OH-A hydroxyl-terminated hydrogenated styrene block copolymer, 0.6 phr (per cent) of bis(1-(tert-butylperoxy)-1-methylethyl)-benzene (BIPB) as an organic peroxide, 3.0 phr of azodicarbonamide (AC) as a foaming agent, 10 phr of calcium carbonate, 1 phr of zinc oxide and 1 phr of stearic acid were mixed and kneaded for 10 minutes in a roll mill at a roll surface temperature of 120° C., and then the mixture was molded into a sheet shape. The added amounts of BIPB, AC, calcium carbonate, zinc oxide and stearic acid were based on the total weight of the resin composition.

[0172] The obtained sheet was filled into a press mold and then heated at 175°C and 100 kgf / cm 2The foam was heated under pressure for about 10 minutes to obtain a foam. The dimensions of the pressing mold were 10 mm in thickness, 150 mm in length, and 150 mm in width. Subsequently, the properties of the foam were measured according to the method. The results are shown in Table 1 below.

[0173] SEB-OH-A foam

[0174] 100 parts of SEB-OH-A, 0.35 phr (per cent) of bis(1-(tert-butylperoxy)-1-methylethyl)-benzene (BIPB) as an organic peroxide, 3.0 phr of azodicarbonamide (AC) as a foaming agent, 10 phr of calcium carbonate, 1 phr of zinc oxide and 1 phr of stearic acid were mixed and kneaded for 10 minutes in a roll mill at a roll surface temperature of 120° C., and then the mixture was molded into a sheet shape. The added amounts of BIPB, AC, calcium carbonate, zinc oxide and stearic acid were based on the total weight of the resin composition.

[0175] The obtained sheet was filled into a press mold and then heated at 175°C and 100 kgf / cm 2 The cross-linked foam was heated under pressure of 1000 g for about 10 minutes to obtain a cross-linked foam with an expansion ratio of 160%. The dimensions of the pressing mold were 10 mm in thickness, 150 mm in length, and 150 mm in width. Subsequently, the properties of the foam were determined according to the method. The results are shown in Table 1 below.

[0176] SEB-OH-A foam

[0177] The foams were prepared and tested in the same manner as SEBS-OH-A, except that 100 parts of SEB-OH-A, 0.35 phr of BIPB and 3.0 phr of AC were used. The results are shown in Table 1 below. The foams of the hydroxyl-terminated hydrogenated triblock copolymer SEBS-OH-A and the foams of the hydroxyl-terminated hydrogenated diblock copolymer SEB-OH-A both showed excellent foam properties.

[0178] Table 1: Foam properties

[0179] The examples and comparative examples listed in Table 3 are foam samples used to evaluate the adhesion between the foam samples and the vulcanized rubber sheets. The adhesion test adopts the above-mentioned adhesion evaluation method for the foam containing the hydroxyl-terminated hydrogenated block copolymer. The preparation method of the foam samples is the same as that of SEBS-OH-A, except that the polymer composition is different and the BIPB and AC contents are different. The resin composition, BIPB and AC contents of the foam formulations used in the foam samples are listed in Table 2. For example, the foam of Example 1 is prepared by foaming a formula containing 60 parts of OBC-9530, 40 parts of SEB-OH-B, 0.5 phr of BIPB and 2.0 phr of AC.

[0180] Comparative Example 1 in Table 3 is EVA 659 foam, which is a resin widely used in footwear foam applications. The adhesion value is considered to be a benchmark for evaluating the adhesion ability of foam resins used in footwear foam applications.

[0181] As shown in Table 3, unlike polar EVA 659 foam, the foam of POE-8450 and OBC-9530 has very low adhesion. Compared with POE-8450, a random copolymer of ethylene and 1-octene, the adhesion of OBC-9530, an olefin block copolymer of ethylene and 1-octene, is even lower. With the increase of EVA 659 content, the foam of EVA 659 blends with POE 8450 and OBC9530 respectively shows increased adhesion. In the foam containing 40wt% of EVA, the peel adhesion value of Comparative Example 4 and Comparative Example 7 is still less than 2kgf / cm. In Comparative Examples 3 and 6, as EVA becomes the main phase, the foam shows good adhesion. In the case of Comparative Example 3, the presence of 40wt% of OBC-9530 in the blend greatly reduces adhesion.

[0182] The foams containing hydroxyl terminated hydrogenated diblock SEB-OH or triblock SEBS-OH all showed excellent adhesion. Quite unexpectedly, the foam samples containing 40 wt% SEB-OH-B, SEB-OH-C or SEBS-OH-B as the minor phase still achieved high adhesion. In the peel adhesion test of pure SEBS-OH-C in Example 9, the foam was torn due to the strong interfacial adhesion.

[0183] Figure 1The following is a photograph of the peeled foam after the peel adhesion test. Obviously, the bonding of Comparative Examples 4 and 7 failed in an adhesive failure mode, while the bonding of Examples 5 and 8 failed in a cohesive failure mode. More specifically, the rupture position of the foam containing the hydroxyl-terminated hydrogenated styrene block copolymer is located in the foam itself, rather than the bonding interface. This result verifies that the foam containing the hydroxyl-terminated hydrogenated styrene block copolymer disclosed in the present invention has foam residues on both surfaces, showing a higher bonding ability.

[0184] Table 2: Foam formulations of foam samples

[0185] Table 3: Properties of foam samples

[0186] Although the present invention has been explained in conjunction with the embodiments thereof, it should be understood that many other possible modifications and variations may be made without departing from the spirit and scope of the present invention as claimed.

[0187] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A foamed body formed by foaming a resin composition, comprising: A hydroxyl-terminated hydrogenated styrene block copolymer, wherein the hydroxyl-terminated hydrogenated styrene block copolymer is a linear block copolymer represented by the following formula: (AB)n-OH, (BA)n-OH, A(BA)n-OH or B(AB)n-OH, wherein n is 1 to 4 and has a hydroxyl group at the end, wherein the A block comprises a styrene monomer unit before hydrogenation, and the B block comprises a conjugated diene monomer unit before hydrogenation; The hydroxyl-terminated hydrogenated styrene block copolymer comprises 10 to 60 wt % of the A block; before hydrogenation, the 1,2-vinyl bond content in the conjugated diene monomer unit of the hydroxyl-terminated hydrogenated styrene block copolymer is 5 to 60 mol %; after hydrogenation, 40 mol % or more of the conjugated diene monomer unit is hydrogenated; and the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000.

2. The foam according to claim 1, wherein The hydroxyl-terminated hydrogenated styrene block copolymer is a linear diblock copolymer represented by the formula AB-OH or BA-OH.

3. The foam according to claim 1, wherein The hydroxyl-terminated hydrogenated styrene block copolymer is prepared by an anionic polymerization process of sequentially polymerizing the A block and the B block. The anionic polymerization process contains a terminal hydroxyl group, and the hydroxyl group is located at the end of the A block or the end of the B block.

4. The foam according to claim 1, wherein The A block is a polymer block of a styrene monomer unit, the B block is a polymer block of a conjugated diene monomer unit, and the conjugated diene monomer unit is selected from the group consisting of a butadiene unit, an isoprene unit and a combination thereof.

5. The foam according to claim 1, wherein The A block is a polymer block of a styrene unit and a conjugated diene monomer unit, wherein the conjugated diene monomer unit is a butadiene unit, an isoprene unit or a combination thereof, and the content of the conjugated diene monomer unit in the A block is less than or equal to 15wt% of the total weight of the A block.

6. The foam according to claim 1, wherein The A block is a polymer block of styrene units, and the B block is a polymer block of butadiene units.

7. The foam according to claim 1, wherein The B block is a polymer block of butadiene units and styrene units, wherein the content of the styrene units in the total weight of the B block is less than or equal to 20 wt %.

8. The foam according to claim 4, wherein Before hydrogenation, the 1,2-vinyl bond content of the butadiene units is 5 to 60 mol%.

9. The foam according to claim 5, wherein Before hydrogenation, the 1,2-vinyl bond content of the butadiene units is 5 to 60 mol%.

10. The foam according to claim 6, wherein Before hydrogenation, the 1,2-vinyl bond content of the butadiene units is 5 to 60 mol%.

11. The foam according to claim 7, wherein Before hydrogenation, the 1,2-vinyl bond content of the butadiene units is 5 to 60 mol%.

12. The foam according to claim 4, wherein Before hydrogenation, the 3,4-vinyl bond content of the isoprene units is 5 to 60 mol%.

13. The foam according to claim 5, wherein Before hydrogenation, the 3,4-vinyl bond content of the isoprene units is 5 to 60 mol%.

14. The foam according to claim 1, wherein After hydrogenation, 60 to 95 mol% of the conjugated diene monomer units are hydrogenated.

15. A foamed body formed by foaming a resin composition, comprising: (a) a hydroxyl-terminated hydrogenated styrene block copolymer, wherein the hydroxyl-terminated hydrogenated styrene block copolymer is a linear block copolymer represented by the following formula: (AB)n-OH, (BA)n-OH, A(BA)n-OH or B(AB)n-OH, wherein n is 1 to 4 and has a hydroxyl group at the end, wherein the A block comprises a styrene monomer unit before hydrogenation, and the B block comprises a conjugated diene monomer unit before hydrogenation; wherein the hydroxyl-terminated hydrogenated styrene block copolymer comprises 10 to 60 wt % of the A block; before hydrogenation, the 1,2-vinyl bond content in the conjugated diene monomer units of the hydroxyl-terminated hydrogenated styrene block copolymer is 5 to 60 mol %; after hydrogenation, 40 mol % or more of the conjugated diene monomer units are hydrogenated; and the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000; and (b) ethylene copolymers; The weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the ethylene copolymer is 90 / 10 to 10 / 90.

16. The foam according to claim 15, wherein The ethylene-based copolymer is an ethylene-vinyl acetate copolymer, an olefin block copolymer including a polymer block of ethylene units, an ethylene α-olefin-based random copolymer, polyethylene or a combination thereof.

17. The foam according to claim 15, wherein The ethylene-based copolymer is an ethylene-vinyl acetate copolymer, and the content of vinyl acetate in the ethylene-vinyl acetate copolymer accounts for 15 to 40 wt % of the total weight of the ethylene-vinyl acetate copolymer.

18. The foam according to claim 15, wherein The ethylene copolymer is an ethylene α-olefin-based random copolymer composed of ethylene units and octene units.

19. The foam according to claim 15, wherein The ethylene copolymer is an olefin block copolymer, which comprises a polymer block of octene units.

20. The foam according to claim 15, wherein The ethylene copolymer is an olefin block copolymer having a melting point of 110° C. to 130° C. and a density of 0.875 g / cc to 0.945 g / cc.

21. A foamed body formed by foaming a resin composition, comprising: (a) a hydroxyl-terminated hydrogenated styrene block copolymer, wherein the hydroxyl-terminated hydrogenated styrene block copolymer is a linear block copolymer represented by the following formula: (AB)n-OH, (BA)n-OH, A(BA)n-OH or B(AB)n-OH, wherein n is 1 to 4 and has a hydroxyl group at the end, wherein the A block comprises a styrene monomer unit before hydrogenation, and the B block comprises a conjugated diene monomer unit before hydrogenation; wherein the hydroxyl-terminated hydrogenated styrene block copolymer comprises 10 to 60 wt % of the A block; before hydrogenation, the 1,2-vinyl bond content in the conjugated diene monomer units of the hydroxyl-terminated hydrogenated styrene block copolymer is 5 to 60 mol %; after hydrogenation, 40 mol % or more of the conjugated diene monomer units are hydrogenated; and the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000; and (b) polar thermoplastic elastomers; The weight ratio of the hydroxyl-terminated hydrogenated styrene block copolymer to the polar thermoplastic elastomer is 90 / 10 to 10 / 90.

22. The foam according to claim 21, wherein The polar thermoplastic elastomer is thermoplastic polyurethane, thermoplastic polyester elastomer, polyether block amide or a combination thereof, wherein the polar thermoplastic elastomer has a hardness of 60A to 90A measured by shore A and a melting point of 140° C. to 200° C.

23. The foam according to claim 1, which is obtained by a process comprising injection molding the resin composition in an injection mold, wherein: The process includes: crosslinking the resin composition using an organic peroxide initiator, and foaming the resin composition using a chemical blowing agent; The crosslinking temperature in the injection mold is about 150°C to about 200°C.

24. The foam according to claim 23, wherein The organic peroxide initiator is bis(1-(tert-butylperoxy)-1-methylethyl)-benzene.

25. The foam according to claim 23, wherein The chemical blowing agent is azodicarbonamide.

26. The foam according to claim 23, wherein A crosslinking aid or a functional chain extender is also used to crosslink the resin composition, wherein the functional chain extender includes at least one functional group selected from the group consisting of anhydride, epoxy and isocyanate to react with the terminal hydroxyl group of the hydroxyl-terminated hydrogenated styrene block copolymer.

27. The foam according to claim 23, wherein The density of the foam is 0.1 to 0.5 g / cm 3 , impact resilience is 50% to 80%, and hardness is 20 to 70.

28. An article formed from the foam of claim 1, which is a footwear component.

29. The article of claim 28, wherein: The footwear component is a midsole.

30. A resin composition comprising: A hydroxyl-terminated hydrogenated styrene block copolymer, wherein the hydroxyl-terminated hydrogenated styrene block copolymer is a linear block copolymer represented by the following formula: (AB)n-OH, (BA)n-OH, A(BA)n-OH or B(AB)n-OH, wherein n is 1 to 4 and has a hydroxyl group at the end, wherein the A block comprises a styrene monomer unit before hydrogenation, and the B block comprises a conjugated diene monomer unit before hydrogenation; The hydroxyl-terminated hydrogenated styrene block copolymer comprises 10 to 60 wt % of the A block; before hydrogenation, the 1,2-vinyl bond content in the conjugated diene monomer unit of the hydroxyl-terminated hydrogenated styrene block copolymer is 5 to 60 mol %; after hydrogenation, 40 mol % or more of the conjugated diene monomer unit is hydrogenated; and the weight average molecular weight of the hydroxyl-terminated hydrogenated styrene block copolymer is 30,000 to 200,000.

31. The resin composition according to claim 30, further comprising an ethylene copolymer.

32. Use of the resin composition according to claim 30 for preparing a foam.

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