KR20210047305A - Shoes comprising a sole of thermoplastic material and methods used to make such shoes - Google Patents

Abstract

The present invention relates to a new shoe comprising a sole of a thermoplastic material attached to an upper by a hot melt adhesive applied between the sole and the upper, wherein the hot melt adhesive is fused with the thermoplastic material. Advantageously, the fusion _{heats the hot melt adhesive to a temperature T HM} at which the hot melt adhesive softens, and heats the thermoplastic body so that the thermoplastic material with _{the melting temperature T M} achieves a temperature T _{SUB below T M (} It _{is generated by making T HM} + T _SUB )/2 equal to or higher than _{T M -10°C.}

Description

Shoes comprising a sole of thermoplastic material and methods used to make such shoes

The present invention relates to footwear and the manufacture thereof. More specifically, the present invention relates to footwear having a sole of thermoplastic material and a method of making a workpiece that can be used in the manufacture of such footwear.

Modern shoes are made up of the same basic elements. All shoes have a sole that is the sole of the shoe that contacts the ground. The sole can be made of a variety of materials, but most modern shoes have a sole made of natural rubber, polyurethane, polyvinyl chloride (PVC) or ethylene-vinyl acetate copolymer (EVA). The sole is simple and can be a single layer of material, but in most cases it is more complex and has multiple structures or layers and materials. When various layers are used, the sole may consist of an insole (also referred to as a sock liner), a midsole, and an outsole (ie, a layer in direct contact with the ground). The midsole is the layer between the outsole and the insole and is usually present for shock absorption.

Another common element of all shoes is the upper shoe. The upper helps keep the shoe on the foot. In the simplest case, such as sandals or flip-flops, this may be just a few straps to hold the sole in place. Clogged shoes such as boots, sneakers and most men's shoes have a more complex upper. These parts are often decorated or made in a specific style to look attractive. The upper may be connected to the sole with a piece of leather, rubber or plastic stitched between the upper and the sole, or may be glued to the sole using an adhesive. In the manufacture of athletic shoes, the upper is, in most cases, an aqueous solvent (e.g., a water-based PUD, polyurethane adhesive) or a non-aqueous solvent (e.g., polychloroprene or styrene-isoprene-styrene adhesive) to form a solvent-based adhesive. To be glued to the midsole (midsoles are an important item of such shoes). Although solvent-based adhesives are relatively expensive, require inherently long processing times, and may also require special care to avoid environmental damage and adverse health effects (caused by many non-aqueous solvents), these adhesives Is preferred over hot melt adhesives. Hot melt adhesives have the advantage that they are (almost) solvent-free and allow very short processing times with no tendency to foam during processing, but their adhesion properties to relatively smooth soles are relatively poor. This is especially the case when attaching the upper to the outsole of thermoplastic material. The latter type of material is in principle preferred over EVA because it is easier to recycle than the commonly used EVA (typically used for midsoles) (EVA's final foam has thermosetting properties, which is recycled by simply melting the material and reprocessing it). Interfere with doing). In addition, due to the difficulty of adhering the upper to the thermoplastic sole, EVA is still a polymer with the properties of attaching the upper using a solvent-based adhesive.

In particular, the problem of low quality adhesion of the upper to the thermoplastic sole when using a hot melt adhesive has been known for decades.

GB 1247855 (filed in 1967, published in 1971) describes the problem of bonding uppers to plasticized polyvinyl chloride soles using hot melt adhesives. The solution proposed in this patent is to use a polyester hot melt adhesive containing a large amount of nitrogen-containing organic compounds having polar groups such as N-butyl-benzenesulfonamide or N-ethyl-p-tolylsulfonamide. However, these compounds are associated with health risks. N-butyl-benzenesulfonamide is neurotoxic and has been shown to cause spastic myelopathy in rabbits. N-ethyl-p-tolylsulfonamide is toxic and very irritating.

US 3,168,754 (filed in 1961, published in 1965). Also, by the end of the 1950s, although hot melt adhesives were found to be very useful in other fields other than sole attachment, the problem of using hot melt adhesives to attach uppers to the soles was addressed. Mention. According to the '754 patent (columns 1, lines 28-30), "Attempting to bond the sole to the upper using a known hot melt bonding process is obviously unsuitable due to the unsatisfactory penetrability and/or wettability of the surface to be bonded. "It provides adhesion." The proposed solution aimed to increase the penetration and wetting properties of the hot melt adhesive by using a repetitive heating and cooling process. This increases the processing time and may not provide adequate adhesion, especially when adhering to a thermoplastic sole.

US 3,212,115 (filed in 1959, published in 1965) confirms that the use of hot melt adhesives in the manufacture of shoes causes several disadvantages, the most important of which, at the temperature associated with the treatment or use of the bonded structure during implementation. It is that adhesion failure occurs. The proposed solution is to deposit a relatively thick body of molten crystallizable hot melt adhesive on the surface, supercool this adhesive to a temperature lower than the crystallization temperature but higher than the second transition temperature, and remove the body of the supercooled adhesive from the surface. It is a complex method involving deformation of the adhesive body by pressing between two surfaces (wherein the deformation induces crystallization and causes the orientation of the deposited adhesive, which should increase the tensile strength and toughness of the adhesive).

GB 2048897 (filed in 1979, published in 1980) states that it is known that the capacity of elastic sole materials for adhesives and thermoplastics is often unsatisfactory (pages 1, lines 14-16). The proposed solution is to use an aggressive primer comprising an organic halogen donor, such as a mixture of isocyanuric acid chloride and sulfonamide, for example p-toluene sulfonamide, to promote adhesion. This primer is toxic, irritating and not environmentally friendly.

US 6,497,786 (filed in 1997, published in 2002) describes the potential benefits of using solvent-free adhesives, but the need to heat the adhesive to make it possible and apply it, especially when current sole materials are at high temperatures. It is noted that it is a disadvantage because it can be deformed. The '786 patent proposes the use of microwaves to locally heat the adhesive while keeping the sole at a low temperature. However, this solution requires a very complex device to specifically heat the adhesive. In addition, it does not address or solve the problem of improper adhesion when using hot melt adhesives.

It is an object of the present invention to provide a method of assembling a workpiece that can be used to manufacture new footwear and footwear that reduces the drawbacks of the prior art.

In order to meet the object of the present invention, a new shoe has been devised, and the shoe includes a sole made of a thermoplastic material attached to the upper by a hot melt adhesive applied between the sole and the upper, wherein the hot melt adhesive is the thermoplastic material Fused with.

The inventors have surprisingly found that, even when bonding to a body of a thermoplastic material with a very smooth surface, using a standard hot melt adhesive, this method can achieve excellent adhesion when providing a fusion of the thermoplastic material and the hot melt adhesive. did. This discovery suggests that the thermoplastic material itself is not easy to adhere to other materials, especially hot melt adhesives, but it is the upper region of the body (i.e. at least on the molecular scale, at least on the micrometer level, i.e. at least 1 μm, for example 2 , 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100 or more areas with a thickness of µm). , The molten hot-melt adhesive and the molecules in the molten upper region of the thermoplastic body can fuse (i.e., mix and form) a new material that acts as a bridge between the hot-melt adhesive on one side and the thermoplastic body on the other. It was based on the perception that options could be offered.

The present invention also provides a _{step of heating the hot melt adhesive to a temperature T HM} so that the hot melt adhesive can be softened and applied, heating the thermoplastic body so that the thermoplastic material has a T _SUB below its melting temperature, (T _HM + T _SUB It relates to a method for assembling a work piece for use in shoe manufacturing, comprising the step of making )/2 equal to or greater than the melting temperature of the thermoplastic material minus 10° C. (T _{M −10° C.).} When applying this particular temperature, the total heat available is sufficient to melt the upper area of the thermoplastic body when in contact with the hot melt adhesive, especially when applying pressure, e.g. when applying the upper, the fusion of the two molten materials. This is acceptable (here, the molten hot melt adhesive may be applied by itself to the sole prior to application of the upper, or may be pre-applied to this upper and maintained at a sufficient temperature while in contact with the upper alone). Melting of the thin upper region of the thermoplastic body can be performed in a variety of ways (e.g., using hot air or liquid convection, radiation, etc.), but a very simple method provides heat to melt the upper region of the thermoplastic body. To do this, it uses the hot melt adhesive and the heat capacity of the body itself.

In any case, by providing a fusion between the hot melt adhesive and the thermoplastic body, a very strong mechanical bond can be obtained without the application of special organic molecules, primers or complicated heating procedures and equipment.

Justice

"Shoes" is an outer covering for a person's foot, generally having a thick or stiff sole attached to the heel, and an upper portion of a lighter material (also known as an upper), such as a fabric or leather seat. .

A “hot melt adhesive” is a solvent-free (less than 1 or 2% by weight) thermoplastic adhesive. Upon heating, this adhesive softens and can be applied to the substrate. Preferably, the hot melt adhesive undergoes a first phase transition when heated and transformed from solid to liquid.

"Thermoplastic material" is a material (generally a synthetic polymer material) that is plastic and capable of being molded upon heating, cured upon cooling to maintain a desired shape, and performing this process repeatedly and reversibly. The melting temperature (T _M ) of the thermoplastic material is the peak melting temperature as defined in ASTM D3418 measured during the second heating step in a differential scanning calorimetry (DSC) experiment performed at a 10° C./min heating rate. If there are multiple peaks, the first peak (eg, the lowest temperature) corresponding to the melting of the hard block of the thermoplastic elastomer should be taken.

The "primary phase transition temperature" of a material is the temperature at which the material undergoes discontinuous changes in density. Examples of first order transitions are melting (conversion from solid to liquid) and evaporation (conversion from liquid to gas). The glass transition is a second order transition because there is no discontinuous change in density.

A "body" is a three-dimensional solid object with predetermined dimensions.

"Fused" means that by melting or by what appears to be melted together to form a single entity, in particular the boundary between materials and/or at 500 to 1000 times magnification in SEM (Scanning Electronic Microscopy) photographs. It means that it results in no clear boundaries.

“Textile material” is a fibrous material, such as a polymeric yarn, essentially (50% excess, eg 55%, 60%, 65%, 70%, 75%, 80%, 85% or Even in excess of 90%).

A body "consisting of" of a thermoplastic material, wherein the basic structure of the body is made of a thermoplastic material, wherein the material is generally in excess of 50% (by weight), preferably at least 60%, 70%, 80%, 85% , 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% excess or even up to 100% of thermoplastic polymer.

A “workpiece” is an assembly of materials, used to manufacture the final product.

A “smooth” surface is a surface that does not have a regular or irregular protruding pattern that a person perceives as “coarse” tactilely, ie, an average height of more than 100 μm, preferably 90 μm, 80 μm, 70 μm, 60 μm, 50 μm , 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm or even a surface that does not have a protruding pattern greater than 1 μm, and Surfaces without regular or irregular patterns of concave portions or holes visually perceived as the inverse of such protrusions, i.e. average depths greater than 100 µm, preferably 90 µm, 80 µm, 70 µm, 60 µm, 50 µm, 40 µm, It is a surface that does not have a concave pattern of more than 30 µm, 20 µm, 10 µm, 9 µm, 8 µm, 7 µm, 6 µm, 5 µm, 4 µm, 3 µm, 2 µm or even 1 µm.

Embodiment of the invention

Particularly suitable thermoplastic materials for the shoe sole according to the invention are thermoplastic elastomers. Thermoplastic elastomers (TPE), sometimes referred to as thermoplastic rubbers, are a class of copolymers or mixtures of physical polymers composed of materials having both thermoplastic and elastomeric properties. Commercial TPEs can be classified into six general classes, such as styrene block copolymers, thermoplastic olefins, elastomer alloys, thermoplastic polyurethanes, thermoplastic copolyesters, and thermoplastic polyamides.

In one embodiment, a shoe according to the invention has a sole comprising a foamed composition comprising a thermoplastic copolyester elastomer in an amount of 70 to 99% by weight, based on the total amount of the foamed composition. In another embodiment, the foamed composition comprises a thermoplastic copolyester elastomer in an amount of 70 to 99% by weight and a plasticizer in an amount of 1 to 30% by weight, based on the total amount of the foamed composition. Such compositions are disclosed in WO2018134166. Surprisingly, the inventors have found that the presence of a plasticizer in combination with a thermoplastic copolyester elastomer is likely to yield a low-density foam (which is ideally suited as the sole material for a shoe) that exhibits fewer cracks. Low-density, crack-free foams are very attractive as they are an important property in applications where light weight is advantageous, especially in the field of athletic shoes. It is understood that foamed compositions are known to those skilled in the art herein. Preferably, the foamed composition has a density of 0.1 to 0.7 g/cm 3, typically 0.2 to 0.3 g/cm 3, especially when used in athletic shoes. Thermoplastic copolyester elastomers are understood herein as copolymers comprising hard segments constructed from polyester repeat units and soft segments selected from other types of polymers.

In a further embodiment, the thermoplastic copolyester elastomer comprises a hard segment constructed of polyester repeat units derived from one or more aliphatic diols and one or more aromatic dicarboxylic acids or esters thereof, and aliphatic polyethers, aliphatic polyesters, And soft segments selected from the group consisting of aliphatic polycarbonates, dimer fatty acids and dimer fatty diols, and combinations thereof. .

Aliphatic diols generally contain 2-10 C atoms, preferably 2-6 C atoms. Examples are ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, butylene glycol, 1,2-hexanediol, 1,6-hexamethylenediol, 1,4-butanediol, 1,4-cyclo Hexanediol, 1,4-cyclohexane dimethanol and mixtures thereof. Preferably 1,4-butanediol is used. Suitable aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4'-diphenyldicarboxylic acid and mixtures thereof. Further, a mixture of 4,4'-diphenyldicarboxylic acid and 2,6-naphthalenedicarboxylic acid or a mixture of 4,4'-diphenyldicarboxylic acid and terephthalic acid is very suitable. The mixing ratio between 4,4'-diphenyldicarboxylic acid and 2,6-naphthalenedicarboxylic acid or the mixing ratio between 4,4'-diphenyldicarboxylic acid and terephthalic acid is preferably a thermoplastic copolyester In order to optimize the melting temperature of, it is selected between 40:60 and 60:40 on a weight basis.

The hard segment is preferably ethylene terephthalate (PET), propylene terephthalate (PPT), butylene terephthalate (PBT), polyethylene bibenzoate, polyethylene naphthalate, polybutylene bibenzoate, polybutylene naphthalate, It has repeating units selected from the group consisting of polypropylene bibenzoate and polypropylene naphthalate and combinations thereof. Preferably, the hard segment is butylene terephthalate (PBT), and the thermoplastic copolyester elastomer comprising the hard segment of PBT exhibits advantageous crystallization behavior and high melting point, so that the thermoplastic copolyester elastomer has excellent processing properties and excellent heat resistance. And chemical resistance.

The soft segment selected from aliphatic polyesters has repeat units derived from aliphatic diols and aliphatic dicarboxylic acids or repeat units derived from lactones. Suitable aliphatic diols generally contain 2-20 C atoms, preferably 3-15 C atoms, in the chain, and aliphatic dicarboxylic acids contain 2-20 C atoms, preferably 4-15 C atoms. Contains. Examples of these include ethylene glycol, propylene glycol, butylene glycol, 1,2-hexanediol, 1,6-hexamethylenediol, 1,4-butanediol, cyclohexanediol, cyclohexanedimethanol, and mixtures thereof. . Preferably 1,4-butanediol is used. Suitable aliphatic dicarboxylic acids are sebacic acid, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, adipic acid, glutaric acid, 2-ethylsuberic acid, cyclopentanedicarboxylic acid. Acid, decahydro-1,5-naphthylene dicarboxylic acid, 4,4'-bicyclohexyl dicarboxylic acid, decahydro-2,6-naphthylene dicarboxylic acid, 4,4'-methylene Bis(cyclohexyl)carboxylic acid and 2,5-furan dicarboxylic acid. Preferred acids are sebacic acid, adipic acid, 1,3-cyclohexane dicarboxylic acid, and 1,4-cyclohexane dicarboxylic acid. Most preferred is adipic acid. Preferably, the soft segment is polybutylene adipate (PBA) obtainable from 1,4 butanediol and adipic acid.

The soft segment may be an aliphatic polyether, which may comprise units of polyalkylene oxides such as polyethylene oxide and polypropylene oxide, and polytetramethylene oxide and combinations thereof as individual segments or in combination into one segment. . The combination is for example ethylene oxide-capped polypropylene oxide.

A preferred soft segment is polytetramethylene oxide (PTMO). In addition, a soft segment comprising a block copolymer, wherein the two types of glycols react to form a soft segment based on, for example, polyethylene oxide (PEO) and polypropylene oxide (PPO) can be used. The soft segment is also referred to as PEO-PPO-PEO, where the PEO block is at the distal end of the soft segment because PEO reacts best with the hard segment. Soft segments based on PTMO, PPO and PEO allow for foams with lower densities.

The soft segment may be an aliphatic polycarbonate, which is composed of repeating units of one or more alkylene carbonates. Preferably, the alkylene carbonate repeat unit is represented by the formula:

Here, R ₁ is alkyl and X is 2 to 20.

Preferably R ₁ = CH ₂ and x = 6, and thus the alkylene carbonate is hexamethylene carbonate, which gives the product high heat resistance and is readily available.

The soft segment can be a dimer fatty acid or a dimer fatty diol and combinations thereof. Dimerized fatty acids can contain from 32 to up to 44 carbon atoms. Preferably the dimerized fatty acid contains 36 carbon atoms. Also suitable are dimer fatty diols which can be derived from dimer fatty acids as disclosed above. For example, a dimerized fatty diol can be obtained as a derivative of a dimerized fatty acid by hydrogenation of a carboxylic acid group of a dimerized fatty acid or an ester group formed therefrom. Further derivatives can be obtained by converting a carboxylic acid group or an ester group formed therefrom into an amide group, a nitrile group, an amine group or an isocyanate group.

In a preferred embodiment, the foamed composition comprises a thermoplastic copolyester elastomer having hard and soft segments, wherein the hard segment is selected from PBT or PET, preferably PBT, and the soft segment is polybutylene adie Selected from the group consisting of pate (PBA), polyethylene oxide (PEO), polypropylene oxide (PPO), polytetramethylene oxide (PTMO), PEO-PPO-PEO and combinations thereof, preferably PTMO, which Provides an article exhibiting low density. In a further preferred embodiment, the foamed composition comprises a thermoplastic copolyether-ester elastomer composed of PBT and PTMO.

Plasticizers are substances known per se to those skilled in the art and, for example, lower the hardness of the composition and/or increase the strain at break of the composition when compared to the elastomer itself. The plasticizer is present in an amount of 1 to 30% by weight, preferably 5 to 25% by weight, more preferably 8 to 20% by weight, based on the total amount of the foamed composition. Plasticizers are, for example, phthalate esters, dibasic acid esters, melitates and esters thereof, cyclohexanoate esters, citrate esters, phosphate esters, modified vegetable oil esters, benzoate esters and petroleum oils, and these Includes a combination of. Preferably, the plasticizer is triphenyl phosphate (TPP), tert-butylphenyl diphenyl phosphate (Mono-t-but-TPP), di-tert-butylphenyl phenyl phosphate (bis-t-but-TPP), tris( p-tert-butylphenyl) phosphate (tri-t-but-TPP), resorcinol bis (diphenyl phosphate) (RDP), dichloropropyl phosphate, bisphenol A bis- (diphenyl phosphate) (BDP), tricre Syl phosphate (TCP), triethyl phosphate, tributyl phosphate (TBP), tri-2-ethylhexyl phosphate, trimethyl phosphate, epoxidized soybean oil (ESO), epoxidized palm oil (EPO), epoxidized linseed oil ( ELO), argan oil, and combinations thereof.

Alternatively, the shoe according to the invention comprises a sole of a thermoplastic material attached to the upper using a hot melt adhesive applied between the sole and the upper, wherein the hot melt adhesive is fused with a thermoplastic material, and the sole is a thermoplastic polyurethane ( TPU). Advantageously, the sole comprises TPU in an amount of 70 to 100% by weight based on the total amount of the sole composition. Advantageously, the sole may comprise expanded (ie, foamed) TPU as disclosed in WO94/20568 or US2010/0222442. Thermoplastic polyurethanes and their manufacturing processes are well known. TPU is a block copolymer consisting of alternating sequences of hard and soft segments or domains formed by the reaction of (1) diisocyanate and short-chain diol (so-called chain extender) and (2) diisocyanate and long-chain diol. It is coalescence. A wide variety of TPUs can be prepared by changing the proportion, structure and/or molecular weight of the reactive compounds. Preferably, polyester-based TPUs, for example those derived from adipic acid esters, are used in the sole.

In other embodiments, the upper includes a layer of textile material adjacent to the sole. The fabric material appears to be ideally suited for connection to the sole via hot melt adhesive, without special measures, perhaps due to the irregular surface provided by the constituent yarns. The textile material may include polymeric yarns, such as yarns made of polyester polymers. This is particularly advantageous when the sole is made of polyester material, which makes it possible to easily recycle the assembly of the upper and the sole. In the context of the present invention, insoles, midsoles and outsoles are all considered soles.

In one embodiment, the hot melt adhesive is (co)polyurethane(s), (co)polycarbonate(s), (co)polyester(s), (co)polyamide(s), (co)poly(ester) -Amide)(s), mixtures thereof and/or copolymers thereof, as a main component (ie, in an amount of 50% by weight or more of the adhesive composition). Preferably, the hot melt adhesive contains (co)polyester as a main component. (Co) Polyester is terephthalic acid, isophthalic acid, succinic acid, suberic acid, pimelic acid, adipic acid, fumaric acid, maleic acid, itaconic acid, dimer fatty acid, sebacic acid, azelaic acid, sulfoisophthalic acid or a metal salt thereof , 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, furan dicarboxylic acid, trimellitic anhydride and/or dialkyl esters thereof, with an acid selected from mixtures thereof, ethylene Glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, neopentyl glycol, diethylene glycol, triethylene glycol, 1,8-octanediol, 2,2,4-trimethyl- 1,3-pentanediol, polyethylene glycol, polypropylene glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2 ,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 2 ,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butanediol, dimer fatty acid diol, glycerol, pentaerythritol, di-pentaerythritol and/or mixtures thereof. It can be prepared from. Dimeric fatty acids, dimer fatty diols and/or dimer fatty diamines (available from, for example, Croda) can also be used as potential building blocks for obtaining polymers.

Preferably, the (co)polyester is at least selected from terephthalic acid, 2,5-furan dicarboxylic acid, adipic acid, fumaric acid, dimer fatty acid, sebacic acid, azelaic acid, succinic acid and/or combinations thereof. It can be obtained and/or obtained by reacting one acid with at least one alcohol selected from ethylene glycol, 1,6-hexanediol, 1,4-butanediol, dimer fatty acid diol and/or combinations thereof.

Esterification polymerization processes for preparing polyesters for use in the compositions of the present invention are well known in the art and need not be described in detail here. In general, it is sufficient to state that they are generally carried out in a molten state while optionally using a catalyst such as a titanium- or tin-based catalyst and removing the water (or alcohol) formed in the condensation reaction. Preferably when the polyester resin comprises a carboxylic acid functional group, it is derived from polyacids and/or anhydrides.

In another embodiment, the upper, hot melt adhesive and sole are made of polyester material.

In another embodiment of the footwear according to the invention, the hot melt adhesive is semi-crystalline (i.e., at least partially converted to crystals when solidified under equilibrium conditions), preferably 1 to 80 J/g , More preferably 5 to 60 J/g, even more preferably 10 to 40 J/g of melting enthalpy. The determination of the enthalpy of melting is based on ASTM Standard D3418 ("Standard Test Method for Enthalpy of Melting and Crystallization and Transition Temperature of Polymers by Differential Scanning Calorimeters") using a Mettler STARe Differential Scanning Calorimeter. For the actual measurement, about 10 mg of an adhesive sample is placed in a sample cup. This sample is stored in an oven at 150° C. for 15 minutes. The sample is then cooled to 50° C. and then heated to 250° C. at a rate of 5° C./min. The sample is held at 250° C. for 1 minute, immediately after which it is cooled to 25° C. at a rate of 5° C./min. The melting enthalpy of the sample polymer is obtained from the obtained DSC data.

As mentioned above, the present invention is also embodied in a method of assembling a work piece that can be used to manufacture a shoe according to the invention, wherein the work piece is placed on the surface of the second body (i.e., the sole). Comprising a first body mechanically connected to the second body by attaching the body (i.e. upper), the second body consisting of a thermoplastic material having a _{melting temperature T M, the method comprising:}

-Heating the hot melt adhesive to a temperature T _HM at which the hot melt adhesive softens;

-Heating the second body so that the thermoplastic material has a temperature T _{SUB below T M;}

-Applying a heated hot melt adhesive to the surface of the heated second body;

-Applying the first body to the second body to form a work piece;

-Cooling the work piece so that the hot melt adhesive cures

Wherein the temperatures are selected such that (T _HM +T _SUB )/2 is equal to or higher than _{(T M -10°C).}

The technical features of any of the above-described specific embodiments of the footwear according to the invention can also be combined with this method.

In another embodiment of the method of assembling the workpiece, the second body is heated as a whole. This heating can be achieved, for example, by warming the entire second body in an oven or microwave or in a heated mold. Thus, this heating is different from partial heating of the upper region, which can be achieved by external radiation or convection, ie heating only the outside of the second body.

Specifically, in this method, the temperatures are, (T _HM +T _SUB )/2 from T _M to -10, -9, -8, -7, -6, -5, -4, -3, -2,- 1, 0, +1, +2, +3, +4, +5, +6, +7, +8, +9, +10, +11, +12, +13, +14, +15, + It is selected to be different by a temperature difference selected from the group consisting of 16, +17, +18, +19 or +20°C. The larger the temperature difference value, the more the upper region of the thermoplastic body is melted. Advantageously, however, this part should not be too large, since it can negatively affect the shape and mechanical properties without increasing the adhesive strength of the thermoplastic body. Therefore, the preferred upper limit is 20°C.

In another embodiment, _{the second body is heated so that the thermoplastic material has a temperature T SUB} that is less than or equal to X° C. below _{T M} , where X is 100, 90, 80, 70, 60, 55, 50, 45, 40, 35 And 30 is selected from the group consisting of. It has been found that it is desirable that the thermoplastic body is not heated to a temperature too close to its melting temperature.

The invention will now be further illustrated using the following non-limiting embodiments.

1 schematically shows the interaction between the hot melt adhesive and various substrates.
Figure 2 schematically shows the constituent members of the work piece used to manufacture shoes.
3 schematically shows a cross-section of a material used for an upper of a running shoe.
4 schematically shows a test setup for measuring the strength of a mechanical bond due to a hot melt adhesive.
5 is a SEM photograph of the bonded thermoplastic body of Example 1. FIG.

Example 1 describes the bonding of two thermoplastic bodies using a hot melt adhesive.

Figure 1 schematically shows the interaction between the hot melt adhesive 4 and the various substrates 200, 200' and 200". In Figure 1A, a hot melt adhesive layer 4 in a cured form (and thus in a liquid form) is shown. The interaction between application and then cooling below the solidification temperature) and the non-smooth surface of the body 200. The surface of the body has various protrusions 201 and recesses that serve as anchor points for the cured hot melt adhesive. There is 202. This provides a good mechanical bond between the hot melt adhesive 4 and the body 200.

In Fig. 1B, a situation where the body 200' has a smooth surface and there is no anchor point for the hot melt adhesive 4 is shown. This means that the mechanical bond (if any) between the layer of hot melt adhesive 4 and the body 200' is very weak. The layers can be easily separated using a slight pulling force on one of the layers.

In Figure 1C, a situation is depicted in which the body 200" is made of a thermoplastic material and the hot melt adhesive is sufficiently heated immediately prior to application such that the upper region of the body 200" is heated above its melting temperature. In this way, the molecules of the molten hot melt adhesive and the molten body 200" can be mixed and integrated (fused) to form a single new intermediate material 204, which ultimately (the After solidification) it can serve as a mechanical crosslink between the hot melt adhesive layer 4 and the body 200". Although shown as individually identifiable layers in the schematic diagram of Fig. 1C, in practice layer 4 and body 200" gradually change from one pure material to another with a mixture of progressively varying compositions. do.

2 schematically shows the constituent members of the work piece 1 for use in the manufacture of footwear (it need not be more than the work piece itself). In the figure, member 2 is the (middle) sole of the shoe, in this case, 85% by weight of copolyether-ester elastomer (55% by weight relative to the amount of copolyether-ester elastomer) relative to the total amount of the foamed composition. Of PTMO and 45% by weight of PBT) and 15% by weight of epoxidized soybean oil as plasticizer, which provides a foam having _{a density of 0.24 g/cm 3 and a T M of 160°C.} do. The upper 3 consists of a fabric base layer and a topcoat of polyurethane (see Fig. 3). The member 30 is a segment of the upper 3 used to attach the upper 3 to the sole 2 using a hot melt adhesive (see Example 1). The outsole 20 is depicted by the dotted line.

3 schematically shows a cross-section of the material used for the upper 3 of a running shoe. The upper 3 consists of a fabric base layer 31 and a topcoat of polyurethane 32. The fabric layer 31 is the layer that will be used to form a bond with the sole as shown in FIG. 2.

4 schematically shows a test setup (according to the standardized method ASTM D3936) for measuring the strength of the mechanical bonds caused by hot melt adhesives. In this setup, the two bodies 2 and 3 of width L are mechanically bonded with a layer of hot melt adhesive 4. These layers separate at one end, which creates a separation force F. The F/L must be greater than 30 Newtons/inch (11.8 Newtons/cm) to make a suitable shoe.

Example 1

Example 1 describes bonding of a thermoplastic body using a hot melt adhesive. Two thermoplastic bodies were selected to evaluate whether the first body could be adhered to the thermoplastic body using a hot melt adhesive, in this case, the foamed thermoplastic body described in connection with FIG. 2 was selected. The melting temperature T _M of this body is 160° C. (measured by ASTM D3418-03 as described in this patent application). In the first trial, a polyester hot melt adhesive with a melting enthalpy of 27±3 J/g (the measurement was based on ASTM standard D3418 using a Mettler STARe differential scanning calorimeter) was used, and (solid to liquid) 1 The difference transition temperature was about 110°C. The hot melt adhesive was heated to a temperature of 180° C., which is much higher than its melting temperature and is the typical level used to obtain strong bonds using this hot melt. The thermoplastic body was preheated to various temperatures ranging from 80° C. to 100° C. before the hot melt adhesive was applied, and this temperature was (T _HM + T _SUB )/2 in the range of 130 to 140° C., that is, 30° C. to 20° C. than _{T M} It means it is below. The two bodies were pressed together immediately after application of the adhesive. In no case could a good mechanical bond be obtained. The F/L was less than the 5 N/inch value for each work piece. This confirmed the common knowledge that thermoplastic materials could not be properly bonded using a hot melt adhesive.

In a second trial, the hot melt adhesive is heated to 210° C. (ie, the temperature at which the polyester hot melt adhesive decomposes or begins to decompose, i.e., much lower than about 250° C.), and the thermoplastic body is heated to a temperature in the range of 120 to 130° C. Heated to, which means that (T _HM + T _SUB )/2 is in the range of 165 to 170° C., that is, 5° C. to 10° C. delegation than _{T M.} A molten adhesive was provided on one or both of the bodies. In addition to the type of polyester adhesive used in the first experiment ("Type 1"), other types ("Type 2") were used. By keeping all the other parameters the same as in the first experiment, it was possible to obtain a very good mechanical bond between the two thermoplastic bodies. The data are shown in Table 1 below. FIG. 5 shows a SEM (Scanning Electronic Microscopy) photograph, which shows that when a Type 2 adhesive is used at 650 times magnification, the boundary between thermoplastic bodies cannot be distinguished. In FIG. 5, the upper 3 is coupled to the midsole 2 in the same manner as schematically shown in FIG. 2.

This does not depend on specific organic binding molecules, primers or complex heat-cooling cycles, but simply _{by selecting the temperature such that (T HM} + T _SUB )/2 is above (T _M -10°C), for various hot melt adhesives ( It clearly shows that it can provide a very) high mechanical strength bond.

Table 1 : Strength of mechanical bonds using various hot melt adhesives

The experiment was also conducted using a thermoplastic body composed of a foamed composition comprising TPU. Similar results were obtained, thus providing a bond with high mechanical strength.

Claims (17)

A shoe comprising a sole made of a thermoplastic material attached to the upper by a hot melt adhesive applied between the sole and the upper shoe, wherein the hot melt adhesive is fused with the thermoplastic material. , shoes. The method of claim 1,
A shoe, characterized in that the sole comprises a foamed composition comprising a thermoplastic copolyester elastomer in an amount of 70 to 99% by weight, based on the total amount of the foamed composition. The method of claim 2,
The foamed composition, characterized in that it comprises from 70 to 99% by weight of a thermoplastic copolyester elastomer and from 1 to 30% by weight of a plasticizer, based on the total amount of the foamed composition. The method according to claim 2 or 3,
The thermoplastic copolyester elastomer is a hard segment made from polyester repeating units derived from one or more aliphatic diols and one or more aromatic dicarboxylic acids or esters thereof, and aliphatic polyethers, aliphatic polyesters, aliphatic polycarbonates, dimers. Footwear, characterized in that it comprises a soft segment selected from the group consisting of fatty acids and dimer fatty diols and combinations thereof. The method of claim 4,
The hard segment is ethylene terephthalate (PET), propylene terephthalate (PPT), butylene terephthalate (PBT), polyethylene bibenzoate, polyethylene naphthalate (PEN), polybutylene bibenzoate, polybutylene naphthalate, Polypropylene bibenzoate and polypropylene naphthalate and combinations thereof, the soft segment being selected from the group consisting of aliphatic polyethers, aliphatic polyesters, aliphatic polycarbonates, dimer fatty acids and dimer fatty diols, and combinations thereof It characterized in that it is selected from the group consisting of, shoes. The method of claim 5,
The hard segment is selected from PBT and PET, and the soft segment is polybutylene adipate (PBA), polyethylene oxide (PEO), polypropylene oxide (PPO), polytetramethylene oxide (PTMO), PEO-PPO-PEO and these A shoe, characterized in that it is selected from the group consisting of a combination of. The method according to any one of claims 1 to 6,
The footwear, characterized in that the upper comprises a layer of textile material adjacent to the sole. The method of claim 7,
A footwear, characterized in that the textile material comprises a polymeric yarn. The method of claim 8,
A footwear, characterized in that the polymer yarn comprises a polyester polymer. The method according to any one of claims 1 to 9,
The hot melt adhesive is (co)polyurethane(s), (co)polycarbonate(s), (co)polyester(s), (co)polyamide(s), (co)poly(ester-amide)( S), a mixture thereof and/or a copolymer thereof. The method of claim 10,
Shoes, characterized in that the hot melt adhesive comprises (co)polyester. The method according to any one of claims 1 to 11,
Footwear, characterized in that the hot melt adhesive is semi-crystalline, preferably with a melting enthalpy of 1 to 80 J/g. A method of assembling a workpiece comprising a first body mechanically coupled to a second body by attaching the first body to the surface of the second body, comprising:
The second body is composed of a thermoplastic material having a _{melting temperature T M,}
The above method is
-Heating the hot melt adhesive to a temperature T _HM at which the hot melt adhesive softens;
-Heating the second body so that the thermoplastic material has a temperature T _{SUB below T M;}
-Applying a heated hot melt adhesive to the surface of the heated second body;
-Applying the first body to the second body to form a work piece;
-Cooling the work piece so that the hot melt adhesive cures
Wherein the temperatures are selected such that (T _HM +T _SUB )/2 is equal to or higher than _{(T M -10°C).} The method of claim 13,
The temperatures are, (T _HM +T _SUB )/2 is T _M and -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, + 1, +2, +3, +4, +5, +6, +7, +8, +9, +10, +11, +12, +13, +14, +15, +16, +17, Characterized in that it is selected to be different by a temperature selected from the group consisting of +18, +19 or +20°C. The method of claim 13 or 14,
The second body is heated so that the thermoplastic material has a _{temperature T SUB} that is less than or equal to X° C. than _{T M} , where X is from the group consisting of 100, 90, 80, 70, 60, 55, 50, 45, 40, 35 and 30 A method, characterized in that it is selected. The method according to any one of claims 13 to 15,
Method, characterized in that the second body is heated as a whole. A work piece obtainable by the method according to any one of claims 13 to 16.

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