Transparent thermoplastic polyurethane composition, article produced from composition and use of article

Abstract

Disclosed is a transparent thermoplastic polyurethane composition, the transparent thermoplastic polyurethane composition comprising: at least one pellet of a thermoplastic polyurethane; and an anti-blocking agent applied on the surface of the thermoplastic polyurethane pellet, wherein the anti-blocking agent comprises a hydrophobic surface modified silica. Articles produced from the transparent thermoplastic polyurethane composition and uses of the articles are also provided.

Description

Technical Field

[0001] The present disclosure relates to transparent thermoplastic polyurethanes, articles produced from the transparent thermoplastic polyurethanes, and uses of the articles. Background Art

[0002] Thermoplastic polyurethane (TPU) is suitable for many applications such as hoses, pipes, windows, tubing, sporting goods and clothing.

[0003] In most cases, it is desirable for the article to have high clarity, which may be beneficial in optical devices or components.

[0004] After manufacturing, thermoplastic polyurethanes are typically formed into pellets. During transportation and subsequent handling, the pellets must remain free-flowing and not clumping or agglomerating at storage, transportation, and operating temperatures. To prevent sticking, the pellets can be treated with an anti-blocking agent. However, anti-blocking agents, as additives, increase the haze of TPU products made from these pellets.

[0005] EP 1 422 259 A1 discloses thermoplastic polyurethanes with a low tendency for particle surface sticking. These are produced by applying at least one wetting agent meeting specified criteria and at least one solid powdering agent to the TPU before and / or after comminuting the TPU.

[0006] JP5479996B2 discloses a granular resin composition containing a thermoplastic resin and an anti-blocking agent, wherein the anti-blocking agent is a polymer made from a monomer having an ethylenically unsaturated bond.

[0007] There is a need for thermoplastic polyurethane compositions having high clarity and easy processability. Summary of the Invention

[0008] The object of the present invention is to overcome the above-discussed problems of the prior art and to provide a transparent thermoplastic polyurethane.Thermoplastic polyurethane compositions exhibit high optical clarity, low haze and good processability.

[0009] Surprisingly, the present inventors have found that the above objects can be achieved by a thermoplastic polyurethane composition comprising a plurality of thermoplastic polyurethane pellets and an antiblocking agent applied to the surface of the thermoplastic polyurethane pellets, wherein the antiblocking agent comprises hydrophobically surface-modified silica.

[0010] According to another aspect of the present disclosure, an article is provided. The article is produced from a transparent thermoplastic polyurethane composition.

[0011] In a further aspect, the present disclosure provides uses of the article.

[0012] It has surprisingly been found in the present application that by applying an antiblocking agent comprising hydrophobically surface-modified silica to the surface of thermoplastic polyurethane pellets, the resulting thermoplastic polyurethane composition has good processability, high clarity and low haze. DETAILED DESCRIPTION

[0013] Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which this disclosure belongs. As used herein, unless otherwise indicated, the following terms have the meanings assigned to them below.

[0014] As used herein, the articles "a" and "an" refer to one or to more than one (ie, to at least one) of the grammatical object of the article. For example, "an" means one element or more than one element.

[0015] Unless otherwise indicated, all percentages (%) are by weight.

[0016] Unless indicated otherwise, temperature is room temperature and pressure is ambient pressure.

[0017] Thermoplastic polyurethanes are block polymers with soft and hard segments. The soft segments are derived from isocyanates and hydroxyl-terminated polyols, including polyether polyols, polyester polyols, or polycarbonate polyols. The hard segments are derived from isocyanates and chain extenders. The chain extenders are typically one or more small molecule diols, such as 1,3-propylene glycol or 1,4-butanediol. The hard segment content in thermoplastic polyurethane can be calculated by dividing the weight of the chain extender and the weight of the isocyanate reacted with the chain extender by the total weight of the polyurethane.

[0018] The haze measurement of a transparent sample describes the proportion of light that is scattered when it passes through the transparent sample (scattering > 2.5°). Therefore, the haze value quantifies the defects in the material that exist on the surface or within the structure and impair transparency.

[0019] Anti-adhesion agent

[0020] In order to prevent the pellets of thermoplastic polyurethane from adhering to each other, an anti-blocking agent is applied to their surface. The anti-blocking agent can be applied by conventional means, such as spraying, dry mixing, co-extrusion, extrusion together with the pellets, etc.

[0021] The anti-blocking agent according to the present disclosure comprises hydrophobic surface-modified silica.

[0022] Preferably, the silicon dioxide has a 2 / g to 200m 2 / g, preferably within 50m 2 / g to 150m 2 / g, more preferably in the range of 60m 2 / g to 120m 2 Surprisingly, it has been found that hydrophobically surface-modified particulate silica having an average specific surface area within such a range can help reduce the haze caused by the addition of antiblocking agents.

[0023] The hydrophobic surface modified silica is preferably a silica having silyl groups on the surface, the silyl groups including but not limited to trimethylsilyl, triethylsilyl, tripropylsilyl, triisopropylsilyl, tributylsilyl, trihexylsilyl, tricyclohexylsilyl, triphenylsilyl, dimethylsilyl, diethylsilyl, dipropylsilyl, diisopropylsilyl, dibutylsilyl, dihexylsilyl, dicyclohexylsilyl or diphenylsilyl.

[0024] Preferably, the hydrophobic surface-modified silica is a silica having trimethylsilyl, triethylsilyl, tripropylsilyl, triisopropylsilyl, tributylsilyl, trihexylsilyl, tricyclohexylsilyl or triphenylsilyl groups on the surface and having a specific surface area of ​​30 m 2 / g to 300m 2 / g range of silica; or hydrophobic surface modified silica has dimethylsilyl, diethylsilyl, dipropylsilyl, diisopropylsilyl, dibutylsilyl, dihexylsilyl, dicyclohexylsilyl or diphenylsilyl groups on the surface, and the specific surface area is 50m 2 / g to 150m 2 / g range of silica.

[0025] Preferably, the hydrophobic surface-modified silica is a silica having trimethylsilyl, triethylsilyl, tripropylsilyl, triisopropylsilyl, tributylsilyl, trihexylsilyl, tricyclohexylsilyl or triphenylsilyl groups on the surface and having a specific surface area of ​​30 m 2 / g to 190m 2 / g range of silica.

[0026] The hydrophobically surface-modified silica is preferably fumed silica, precipitated silica, or a combination thereof. Fumed silica generally has a large specific surface area and is easy to surface-modify.

[0027] Preferably, the surface-modified silica has a content of 100 ppm to 1,500 ppm, preferably 200 ppm to 1,000 ppm, based on the total weight of the transparent thermoplastic polyurethane composition.

[0028] Many hydrophobic surface modified silicas are known and can be, for example, commercially available from manufacturers such as EvonikResource Efficiency GmbH, Tokuyama Corporation etc. Hydrophobic surface modified silicas can also be prepared in advance by functionalizing the silica surface with a hydrophobic modifier, and the hydrophobic modifier includes but is not limited to alkoxysilanes, halosilanes, aminosilanes and organosilazanes. Exemplary alkoxysilanes, halosilanes, aminosilanes and organosilazanes include but are not limited to methoxytrimethylsilane, methoxytriethylsilane, ethoxytrimethylsilane, chlorotrimethylsilane, aminotrimethylsilane, hexamethyldisilazane, chlorotripropylsilane, chlorotriisopropylsilane, chlorotributylsilyl, chlorotrihexylsilane, chlorotricyclohexylsilane, chlorotriphenylsilane etc. It is known that these compounds can transfer silyl groups to the silica surface and make the silica hydrophobic.

[0029] Isocyanates

[0030] Thermoplastic polyurethanes are based on isocyanates. The isocyanates are preferably organic isocyanates, more preferably diisocyanates. Further preferred isocyanates are selected from the group consisting of aliphatic isocyanates, alicyclic isocyanates, aromatic isocyanates and mixtures thereof.

[0031] In some embodiments, the thermoplastic polyurethane is based on a diisocyanate selected from the group consisting of trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), heptamethylene diisocyanate, octamethylene diisocyanate, 2-methyl-pentamethylene 1,5-diisocyanate, 2-ethyl-butylene-1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate, IPDI), 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane (HXDI), 4,4'-dicyclohexane methylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate, 1-methyl-2,6-cyclohexane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate (TMHDI), 2,4-toluene diisocyanate or 2,6-toluene diisocyanate (TDI), 2,2'-methylene diphenyl diisocyanate, 2,4'-methylene diphenyl diisocyanate or 4,4'-methylene diphenyl diisocyanate (MDI) and any mixtures thereof.

[0032] Preferably, the thermoplastic polyurethane is based on aliphatic or cycloaliphatic diisocyanates.

[0033] More preferably, the thermoplastic polyurethane is based on 4,4′-dicyclohexylmethane diisocyanate, 2,4′-dicyclohexylmethane diisocyanate or 2,2′-dicyclohexylmethane diisocyanate (4,4′-H12MDI, 2,4′-H12MDI or 2,2′-H12MDI) or any mixture thereof.

[0034] polyols

[0035] Polyol refers to a polyhydroxy compound. The polyol forming the thermoplastic polyurethane of the present disclosure includes polyester polyol, polyether polyol, polycarbonate polyol or any combination thereof.

[0036] Preferably, thermoplastic polyurethane-forming polyols having a functionality of 1.5 to 2.5, more preferably 1.8 to 2.3, and preferably a molecular weight of 500 to 5000 g / mol, more preferably 500 to 3000 g / mol, are examples of higher molecular weight compounds having at least two reactive hydrogen atoms.

[0037] Suitable polyester polyols include aliphatic polyester polyols and aromatic polyester polyols. Aliphatic polyester polyols include polymers and copolymers of one or more cyclic lactones (such as caprolactone); polymers and copolymers of hydroxyalkanoic acids such as lactic acid, 3-hydroxypropionic acid or glycolic acid (or their cyclic dianhydride dimers such as lactide or glycolide); and AB-type polyester polyols, which correspond to the reaction products of one or more diols and one or more aliphatic dicarboxylic acids. Aromatic polyester polyols are typically AB-type polyester polyols, which correspond to the reaction products of at least one diol and at least one aromatic carboxylic acid. Polyester polyols contain repeating units corresponding to each diol structure (after removal of each hydroxyl hydrogen) and repeating units corresponding to the dicarboxylic acid structure. As discussed below, various synthetic schemes can be used to prepare AB-type polyesters. "Diol" refers to a compound having exactly two hydroxyl groups per molecule and a molecular weight of at most 300, preferably at most 200, and more preferably at most 100. AB polyester polyols can be prepared with small amounts of branching agents (generally polyols having 3 or more hydroxyl groups per molecule), although such branching agents should be used in small proportions.

[0038] Examples of useful aliphatic AB-type polyester polyols include those corresponding to the reaction products of diols such as 1,4-butanediol, hydroquinone bis(2-hydroxyethyl) ether, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 2-methyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,5-pentanediol, thiodiglycol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol, 1,2-dimethyl-1,2-cyclopentanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,2-dimethyl-1,2-cyclohexanediol, and the like, and dicarboxylic acids such as adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, malonic acid, maleic acid, or fumaric acid.

[0039] Examples of useful aromatic AB-type polyester polyols include those corresponding to reaction products of diols such as 1,4-butanediol, hydroquinone bis(2-hydroxyethyl) ether, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 2-methyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,5-pentanediol, thiodiglycol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol, 1,2-dimethyl-1,2-cyclopentanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,2-dimethyl-1,2-cyclohexanediol, and the like, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, and chlorendic acid.

[0040] Various reaction schemes can be used to form AB type polyester polyol.One or more diacids as above can directly react with one or more glycols as above to prepare polyester. Alternatively, instead of dicarboxylic acid itself or except dicarboxylic acid itself, the anhydride, dialkyl ester and acyl halide of dicarboxylic acid can be used as the raw material in the polyreaction. In some cases, the cyclic oligomer of glycol and dicarboxylic acid (or corresponding dialkyl ester or anhydride) can also be formed, and the cyclic oligomer is polymerized to form polyester. Cyclic oligomer can be prepared by forming low molecular weight polymer and depolymerizing this low molecular weight polymer to form cyclic oligomer by polyol and dicarboxylic acid (or corresponding dialkyl ester or anhydride). Cyclic oligomer can be the cyclic reaction product corresponding to a polyol molecule and a dicarboxylic acid molecule, or can have higher degree of polymerization.

[0041] Another class of polyester polyols is polylactone polyols, such as polycaprolactone, poly(lactic acid) or poly(glycolic acid), which are readily commercially available. These polylactone polyols can be obtained by reacting an initiator, such as a diol, glycerol or amine, with a lactone, such as polycaprolactone, lactide or polyglycolide.

[0042] Various types of polyether polyols are suitable, including, for example, polymers of ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, tetrahydrofuran, and the like. Copolymers of two or more of these may be used. Preferred polyether diols include homopolymers of propylene oxide, random copolymers of propylene oxide and up to 20% by weight of ethylene oxide, random copolymers of propylene oxide-ethylene oxide with terminal poly(ethylene oxide) endcaps, and poly(tetrahydrofuran).

[0043] Polyether diols and polyols having such low unsaturation levels can be prepared using various well-known double metal cyanide catalyst (DMC) complexes.

[0044] Polycarbonates containing hydroxyl groups include those of known types, such as those obtained by the reaction of a diol (e.g., 1,3-propylene glycol, 1,4-butanediol and / or 1,6-hexanediol, 1,10-decanediol, neopentyl glycol, isosorbide, diethylene glycol, triethylene glycol or tetraethylene glycol) with a diaryl carbonate (e.g., diphenyl carbonate) or phosgene.

[0045] Chain Extender

[0046] In addition, in the synthesis of thermoplastic polyurethanes, chain extenders are used as synergistic components. Chain extenders are preferably aliphatic, aromatic, aromatic and / or alicyclic compounds with a molecular weight preferably of 50 g / mol to 500 g / mol, preferably having two groups reactive to isocyanates, which are also referred to as functional groups. Chain extenders are single chain extenders or a mixture of at least two chain extenders. The reaction of isocyanates with chain extenders results in the formation of hard segments in the polyurethane backbone, while polyols form soft segments. The content of hard segments in thermoplastic polyurethanes can be calculated by dividing the sum of the weight of the chain extender and the weight of the isocyanate reacted with the chain extender by the gross weight of the polyurethane. Preferably, based on the gross weight of the thermoplastic polyurethane, the thermoplastic polyurethane has a content of hard segments in the range of 20 wt % to 60 wt %, more preferably in the range of 30 wt % to 45 wt %.

[0047] The chain extender is preferably a difunctional compound, preferred examples being diamines or alkanediols having 2 to 10 carbon atoms in the alkylene radical, or mixtures thereof.

[0048] Preferably, the chain extender is selected from 1,2-ethanediol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, isosorbide and mixtures thereof.

[0049] catalyst

[0050] The catalyst accelerates in particular the reaction between the NCO groups of the isocyanate and the hydroxyl groups of the polyol and the chain extender.Catalysts are optional in the synthesis of thermoplastic polyurethanes.

[0051] Other additives

[0052] In a preferred embodiment, in addition to the antiblocking agent, the composition further comprises additional adjuvants or additives. In a preferred embodiment, the adjuvants or additives are selected from surfactants, nucleating agents, lubricants, release agents, dyes, pigments, antistatic agents, antioxidants, hydrolysis inhibitors, UV absorbers, light stabilizers, heat stabilizers, anti-tarnish agents, inorganic fillers, organic fillers, reinforcing agents, plasticizers, and any combination thereof.

[0053] Production method

[0054] A method for producing a transparent thermoplastic polyurethane composition according to the present disclosure is provided. The method comprises:

[0055] 1). Providing at least one pellet of thermoplastic polyurethane and an anti-blocking agent; and

[0056] 2) applying an anti-blocking agent to the surface of at least one pellet,

[0057] The anti-adhesion agent is hydrophobically surface-modified silica.

[0058] The pellet of thermoplastic polyurethane can be prepared in situ or be ready-made.When pellet in situ is prepared, pellet can be prepared by the construction component of above-mentioned thermoplastic polyurethane or the prepolymer of thermoplastic polyurethane, or by shaped particles, pellet or powder form preparation of commercial thermoplastic polyurethane.In the former case, can use reaction extruder to make the construction component reaction, and then the gained thermoplastic polyurethane is shaped into pellet.In the latter case, thermoplastic polyurethane can be processed and granulated by any known shaping machine.

[0059] The process for preparing thermoplastic polyurethane can be carried out discontinuously or continuously. Preferred processes are reaction extruder processes, endless line processes, "one-step" processes, preferably reaction extruder processes or "one-step" processes, most preferably reaction extruder processes.

[0060] The above-mentioned process is used either by direct mixing of the building components of isocyanate, polyol, chain extender, catalyst, optionally in the presence of additives or auxiliaries, or alternatively by applying a prepolymer process.

[0061] The polyisocyanate prepolymer can be obtained by reacting an excess of the above-mentioned isocyanate with a polyol at a temperature of 30°C to 100°C.

[0062] In the "one-shot" process, the building blocks, isocyanate and polyol, and chain extender, are mixed with one another. In a preferred embodiment, this can occur sequentially or simultaneously in the presence of a catalyst. In the extruder process, the building blocks, diisocyanate, diol, chain extender, and catalyst, are mixed. Mixing in the reactive extrusion process is preferably carried out at temperatures between 100°C and 280°C, preferably between 140°C and 250°C.

[0063] The thermoplastic polyurethane can be formed into pellets or powder after cooling. In a preferred embodiment, the thermoplastic polyurethane is formed in an extruder, more preferably a twin-screw extruder. Twin-screw extruders operate in a forward conveying mode, and therefore the temperature and output of the extruder can be set more accurately.

[0064] After the thermoplastic polyurethane is granulated, an antiblocking agent can be applied to the surface of the pellets. This application can be achieved by methods known to those skilled in the art, including but not limited to blending, spraying, and coating. For example, when preparing pellets, an antiblocking agent in powder form can be applied to a pelletizer and mixed with the pellets to coat their surface.

[0065] The auxiliary agents and additives can be added during the synthesis of the thermoplastic polyurethane, or during the compounding process, or directly added to the pellets of the thermoplastic polyurethane. The former two are preferred. This is especially the case if the additives or auxiliary agents are not inert toward isocyanates, chain extenders, compounds reactive toward isocyanates, or catalysts.

[0066] application

[0067] The transparent thermoplastic polyurethane composition according to the present disclosure can be processed to form an article. Preferably, the article is a cast article, an injection molded article, an extruded article or a laminated article.

[0068] The products are used as plates, sheets, films, laminates, tubes, hoses, or pipes. They can be used in transportation vehicles, buildings, sporting goods, medical devices, and more. High transparency and low haze levels are beneficial for optical performance and visual appearance. For example, flexible displays, protective films, windshields for transportation vehicles, or windows in buildings require high light transmittance and low haze.

[0069] Preferably, the article may be used in automobile windshields, aircraft windows, ballistic glass, or building windows.

[0070] Articles can be produced from the transparent thermoplastic polyurethane composition by various methods known to those skilled in the art, including but not limited to injection molding, extrusion, calendaring, blow molding, lamination, rotational molding, and the like.

[0071] Example

[0072] Measurement and test methods

[0073] (1) Measurement of adhesion effect

[0074] The blocking effect of TPU pellets was measured as follows, where lower values ​​indicate better anti-blocking properties:

[0075] 15 g of TPU pellets (short axis diameter of 2.8 mm to 3.3 mm and long axis diameter of 3.7 mm to 4.2 mm, nearly elliptical pellets) were placed in a 7.5 cm diameter melting dish and maintained at 70° C. for 1 hour.

[0076] Then, the culture dish was turned over and kept in the upside-down state for 1 minute.

[0077] Finally, the two pellets were weighed. The two pellets were:

[0078] Pellets a) adhered to the molten petri dish; and

[0079] Pellets b) Pellets falling from a melting dish.

[0080] The adhesion rate is calculated as:

[0081]

[0082] BR represents the adhesion ratio, and w a and w b Represent the weight of pellets a) and b), respectively.

[0083] (2) Thickness measurement of TPU sheet or film

[0084] Measure the center portion of the TPU sheet or film 10 times with a micrometer, and determine the average value as the thickness of the TPU sheet or film.

[0085] (3) Determination of transmission haze

[0086] The transmission haze of the TPU sheet or film was measured using a haze meter (HAZE METER NDH 5000, NIPPON DENSHOKU IN-DUSTRIAL Co., LTD., Japan) in accordance with JIS K7136 “Plastics—Determination of haze of transparent materials”.

[0087] Material

[0088] The materials used in the examples are as follows.

[0089] Dicyclohexylmethane 4,4′-diisocyanate (H12MDI), Cas No. 5124-30-1, from Wanhua Chemical Group Co., Ltd.

[0090] 1,3-Propanediol, CAS No. 504-63-2, from Okahata Co., Ltd.

[0091] 1,4-Butanediol, CAS No. 110-63-4, from BASF.

[0092] Poly(tetrahydrofuran) (PTHF), Mn=1000 g / mol, CAS No. 25190-06-1, from BASF.

[0093] Silicon dioxide 1 from Evonik Resource Efficiency GmbH NAX-50, a hydrophobically modified fumed silica treated with hexamethyldisilazane, contains trimethylsilyl (TMS) groups and has a specific surface area (SSA) of 30 m 2 / g to 50m 2 / g.

[0094] Silicon dioxide 2 from Evonik Resource Efficiency GmbH NX-130, a hydrophobically modified fumed silica treated with hexamethyldisilazane, containing trimethylsilyl groups, with a specific surface area of ​​80 m 2 / g to 120m 2 / g.

[0095] Silicon dioxide 3, from Tokuyama Corporation HM-20L, hydrophobically modified fumed silica treated with hexamethyldisilazane, contains trimethylsilyl groups and has a specific surface area of ​​135 m 2 / g to 165m 2 / g.

[0096] Silicon dioxide 4 from Evonik Resource Efficiency GmbH R812, hydrophobically modified fumed silica treated with hexamethyldisilane, contains trimethylsilyl groups and has a specific surface area of ​​230 m 2 / g to 290m 2 / g.

[0097] Silicon dioxide 5, from Evonik Resource Efficiency GmbH R972, hydrophobically modified fumed silica treated with dimethyldichlorosilane, contains dimethylsilyl (DMS) groups and has a specific surface area of ​​90 m 2 / g to 130m 2 / g.

[0098] Silicon dioxide 6 from Evonik Resource Efficiency GmbH R976S, hydrophobically modified fumed silica treated with dimethyldichlorosilane, contains dimethylsilyl groups and has a specific surface area of ​​215 m 2 / g to 265m 2 / g.

[0099] Silicon dioxide 7 from Admatechs Co., Ltd. SO-C2, spherical silica, with a specific surface area of ​​4m 2 / g to 7m 2 / g.

[0100] Silicon dioxide 8 from Admatechs Co., Ltd. SO-C1, spherical silica, specific surface area: 10m 2 / g to 20m 2 / g.

[0101] Silicon dioxide 9 from Evonik Resource Efficiency GmbH 50, hydrophilic fumed silica, specific surface area: 35m 2 / g to 65m 2 / g.

[0102] Silicon dioxide 10 from Evonik Resource Efficiency GmbH 130, hydrophilic fumed silica, specific surface area: 105m 2 / g to 155m 2 / g.

[0103] Silicon dioxide 11 from Evonik Resource Efficiency GmbH 300, hydrophilic fumed silica, specific surface area: 270m 2 / g to 330m 2 / g.

[0104] Preparation of TPU sheets

[0105] The thermoplastic polyurethanes used in Examples 1 to 8 and Comparative Examples 1 to 6 were prepared from H12MDI, poly(tetrahydrofuran), and a chain extender consisting of a mixture of 1,4-butanediol (BDO) and 1,3-propylene glycol (PDO) in a weight ratio of 7:3. The hard segment content in the thermoplastic polyurethanes was 35% by weight. The thermoplastic polyurethanes were prepared by mixing and reacting the raw materials. Pellets were produced using a pelletizer.

[0106] The TPU pellets and the antiblocking agent are dry-mixed to form TPU pellets having the antiblocking agent on the surface.

[0107] The thermoplastic polyurethane pellets having an anti-blocking agent on the surface were processed by an injection machine (PLASTAR TM-130F2, Toyo Machinery & Metal Co., Ltd.) at a temperature of 200° C. to form a sheet having a thickness of 2 mm.

[0108] Table 1 lists the haze values ​​for various thermoplastic polyurethane compositions, along with information on antiblocking agents. "TMS" refers to "trimethylsilyl" groups, and "DMS" refers to "dimethylsilyl." Stoichiometry is the number of isocyanate groups divided by the total number of isocyanate-reactive groups (here, the hydroxyl groups in the chain extender and poly(tetramethylenetetrahydrofuran)).

[0109] Table 1 Properties of sheets made from TPU pellets with antiblocking agent

[0110]

[0111] Can be observed from Table 1 that silicon dioxide as anti-blocking agent can reduce adhesion rate.In addition, show that when using the silicon dioxide of hydrophobic surface modification as anti-blocking agent, thermoplastic polyurethane composition can illustrate high transparency and low haze.More interestingly, the thermoplastic polyurethane composition with the silicon dioxide of hydrophobic surface modification containing trimethylsilyl functional group, or some thermoplastic polyurethane compositions with the silicon dioxide of hydrophobic surface modification containing dimethylsilyl functional group, can show than the silicon dioxide of unsurface treatment or the part of the silicon dioxide of hydrophobic surface modification containing dimethylsilyl functional group even lower haze.Among other factors, the specific surface area of ​​anti-blocking agent also has an impact on the haze performance of gained thermoplastic polyurethane composition.Containing trimethylsilyl functional group and specific surface area is 30m 2 / g to 300m 2 / g hydrophobic surface modified silica is particularly useful for obtaining low haze TPU compositions. Similarly, silica containing dimethylsilyl functional groups and having a specific surface area of ​​50m 2 / g to 150m 2The hydrophobic surface modified silica of 1000 μg / g is particularly advantageous. Compared to Comparative Example 5, Example 8 shows much lower haze values.

Claims

1. A transparent thermoplastic polyurethane composition, comprising: at least one pellet of thermoplastic polyurethane; and Anti-blocking agent applied to the surface of thermoplastic polyurethane pellets, The anti-blocking agent comprises hydrophobically surface-modified silica.

2. The transparent thermoplastic polyurethane composition according to claim 1, wherein the hydrophobic surface modified silica has a 2 / g to 200m 2 / g, preferably within 50m 2 / g to 150m 2 / g, more preferably in the range of 60m 2 / g to 120m 2 The specific surface area is within the range of 1.5 ~ 2.5 g / cm2.

3. The transparent thermoplastic polyurethane composition according to claim 1, wherein The hydrophobic surface modified silica has trimethylsilyl, triethylsilyl, tripropylsilyl, triisopropylsilyl, tributylsilyl, trihexylsilyl, tricyclohexylsilyl or triphenylsilyl groups on the surface and has a specific surface area of ​​30 m 2 / g to 300m 2 / g range of silica; or The hydrophobic surface modified silica has dimethylsilyl, diethylsilyl, dipropylsilyl, diisopropylsilyl, dibutylsilyl, dihexylsilyl, dicyclohexylsilyl or diphenylsilyl groups on the surface and has a specific surface area of ​​50 m 2 / g to 150m 2 / g range of silica.

4. The transparent thermoplastic polyurethane composition according to claim 1, wherein the hydrophobic surface-modified silica is a silica having trimethylsilyl, triethylsilyl, tripropylsilyl, triisopropylsilyl, tributylsilyl, trihexylsilyl, tricyclohexylsilyl or triphenylsilyl groups on the surface and having a specific surface area of ​​30 m 2 / g to 190m 2 / g range of silica.

5. The transparent thermoplastic polyurethane composition of claim 1, wherein the hydrophobic surface-modified silica is fumed silica, precipitated silica, or a combination thereof. The transparent thermoplastic polyurethane composition according to claim 1 , wherein the surface-modified silica has a content of 100 ppm to 1,500 ppm, preferably 200 ppm to 1,000 ppm, based on the total weight of the transparent thermoplastic polyurethane composition.

7. The transparent thermoplastic polyurethane composition of claim 1, wherein the thermoplastic polyurethane is based on a chain extender selected from the group consisting of 1,2-ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, isosorbide, and mixtures thereof.

8. The transparent thermoplastic polyurethane composition according to claim 1, wherein the thermoplastic polyurethane has a hard segment content in the range of 20 wt% to 60 wt%, preferably in the range of 30 wt% to 45 wt%, based on the total weight of the thermoplastic polyurethane.

9. The transparent thermoplastic polyurethane composition of claim 1, wherein the thermoplastic polyurethane is based on an aliphatic or alicyclic diisocyanate.

10. The transparent thermoplastic polyurethane composition according to claim 9, wherein the thermoplastic polyurethane is based on 2,2'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate or any mixture thereof.

11. The transparent thermoplastic polyurethane composition according to claim 1 , further comprising an additive selected from the group consisting of a surfactant, a nucleating agent, a lubricant, a mold release agent, a dye, a pigment, an antistatic agent, an antioxidant, a hydrolysis inhibitor, a UV absorber, a light stabilizer, a heat stabilizer, an anti-discoloration agent, an inorganic filler, an organic filler, a reinforcing agent, a plasticizer, and any combination thereof.

12. An article produced from the transparent thermoplastic polyurethane composition according to any one of the preceding claims.

13. The article of claim 12, which is a cast article, an injection molded article, an extruded article, or a laminated article.

14. Use of the article according to claim 12 or 13 as a plate, sheet, film, laminate, tube, hose or pipe.

15. Use of the article according to claim 14 in automobile windshields, aircraft windows, ballistic glass or building windows.

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