JP2020044853A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire that is manufactured using an environmental load reduction type polyethylene naphthalate that uses a non-fossil raw material as a principal raw material for a belt reinforcement material.SOLUTION: A pneumatic tire is manufactured using a belt reinforcement material that includes a polyethylene naphthalate derived from a non-fossil raw material. In a preferable embodiment, the pneumatic tire is manufactured using a polyethylene naphthalate that is manufactured using a raw material derived from a non-fossil raw material for a straight chain part or cyclic part of the polyethylene naphthalate for the belt reinforcement material.SELECTED DRAWING: None

Description

  TECHNICAL FIELD The present invention relates to a pneumatic tire manufactured by using a polyethylene naphthalate with reduced environmental impact, which is constituted by a non-fossil raw material as a belt reinforcing material.

  Most of polyethylene naphthalate used for the belt reinforcing material is manufactured from petroleum-derived raw materials. Many petroleum-derived polyethylene naphthalates are light, tough, durable, easily and arbitrarily moldable, and have been mass-produced to support pneumatic belt reinforcements with excellent performance. Was. However, these polyethylene naphthalates accumulate without being easily decomposed when disposed of in the environment. It also emits a large amount of carbon dioxide during incineration, spurring global warming. In recent years, measures against serious environmental problems such as a decrease in fossil fuels and an increase in atmospheric carbon dioxide have become necessary.In the field of polyethylene naphthalate used for belt reinforcement, raw materials derived from non-fossil raw materials have been used as raw materials. There is a need for polyethylene naphthalate with reduced environmental load.

  During their growth, plants absorb carbon dioxide in the air and immobilize the carbon themselves by photosynthesis. Therefore, using polyethylene naphthalate produced from the plant as a raw material, the carbon dioxide generated when burned after use is the same amount as the carbon dioxide originally absorbed by the plant, so-called carbon neutral, even if burned It does not increase carbon dioxide on Earth.

From such a viewpoint, Patent Document 1 describes an environmental load-reducing polyethylene naphthalate having excellent heat resistance and using a non-fossil raw material as a main raw material. However, Patent Literature 1 does not disclose that this environmental load-reducing polyethylene naphthalate is used as a belt reinforcing material.
Patent Literature 2 discloses that polyethylene naphthalate is used as a carcass material for a tire. However, Patent Document 2 does not describe the origin of the constituent carbon of polyethylene naphthalate, and it is presumed that polyethylene naphthalate derived from fossil raw materials is used.
Further, Patent Literature 3 discloses that polyethylene naphthalate is used as a belt reinforcing material for a tire. However, Patent Document 3 does not describe the origin of the constituent carbon of polyethylene naphthalate, and it is presumed that polyethylene naphthalate derived from fossil raw materials is used.

JP 2010-280750 A JP 2008-290503 A JP-A-5-338403

An object of the present invention is to provide a pneumatic tire manufactured by using environmentally friendly polyethylene naphthalate using a non-fossil raw material as a main raw material for a belt reinforcing material.
Here, the term “environmental load reduction type” specifically means that the substantial amount of carbon dioxide generated when the target polyethylene naphthalate is burned is small.

  As a result of intensive studies by the present inventors under the above problems, the use of non-fossil raw material-derived polyethylene naphthalate impairs performance even when compared with a belt reinforcing material manufactured from conventional fossil raw material-derived polyethylene naphthalate. The inventors have found that the present invention will not be performed, and have completed the present invention.

  That is, the present invention provides a pneumatic tire manufactured by using polyethylene naphthalate derived from a non-fossil raw material as a belt reinforcing material.

The polyethylene naphthalate of the belt reinforcing material of the present invention is a polyethylene naphthalate composed of a non-fossil raw material, having an intrinsic viscosity of 0.50 to 1.00 dL / g and a melting point of 230 ° C. or more. Can be solved.
Hereinafter, when the ¹⁴ C concentration in the circulating carbon as of 1950 in the total carbon atoms in a certain organic compound is defined as a reference (100%), the ¹⁴ C concentration ratio contained in the organic compound at the present time is defined as the organic compound. It is referred to as the "bioconversion rate" of the compound. The principle and method of measuring the concentration ratio will be described later.

ADVANTAGE OF THE INVENTION According to this invention, the environmental load reduction type belt reinforcement using the environmental load reduction type polyethylene naphthalate derived from a non-fossil raw material can be provided.
That is, it is generated when the polyethylene naphthalate constituting the belt reinforcing material of the present invention is burned, as compared with a belt reinforcing material composed of polyethylene naphthalate having the same chemical structure manufactured using a fossil raw material. This has the effect of being a belt reinforcing material in which the substantial emission of carbon dioxide is reduced by at least 400 g per kg of polyethylene naphthalate. Therefore, it is possible to provide a belt reinforcing material that can exhibit the same performance as the conventional belt while reducing the environmental load.

  The non-fossil raw material-derived polyethylene naphthalate of the present invention can be used, for example, as a belt reinforcing material constituting a pneumatic tire. The non-fossil raw material-derived polyethylene naphthalate is produced in the same manner as the conventional polyethylene naphthalate except that a non-fossil raw material-derived raw material is used, and is used for producing a belt reinforcing material.

  In the present invention, a non-fossil raw material-derived raw material refers to a raw material produced from non-fossil biomass resources. Here, non-fossil biomass resources refer to carbon-neutral organic resources derived from renewable organisms that are generated from water and carbon dioxide using solar energy, and include fossil resources obtained from petroleum, coal, natural gas, etc. Excluding resources. That is, such an organic compound as a raw material produced from a non-fossil biomass resource is referred to as the non-fossil raw material described above.

  The biomass resources according to the present invention are classified into three types: waste, unused, and resource crop based on their generation form. Examples of biomass resources include cellulosic crops (pulp, kenaf, straw, rice straw, waste paper, papermaking residue, etc.), lignin, charcoal, compost, natural rubber, cotton, sugarcane, oils and fats (rapeseed oil, cottonseed oil, soybean oil, coconut oil) Glycerol, carbohydrate crops (corn, potatoes, wheat, rice, cassava, etc.), bagasse, terpene compounds, pulp black liquor, garbage, wastewater sludge, and the like. The method for producing the glycol compound from biomass resources is not particularly limited, but a biological treatment method utilizing the action of microorganisms such as fungi and bacteria; acids, alkalis, catalysts, heat energy or light energy, etc. Or a known method such as a physical treatment method such as miniaturization, compression, microwave treatment or electromagnetic wave treatment.

  As a method for producing polyethylene naphthalate from biomass resources, various production methods can be mentioned. The production method is not particularly limited. First, a biological treatment method utilizing the action of microorganisms such as fungi and bacteria from biomass resources; a chemical treatment method using an acid, an alkali, a catalyst, heat energy or light energy, or the like. Or a known method such as a physical treatment method such as miniaturization, compression, microwave treatment, or electromagnetic wave treatment is performed. Next, there is a method of purifying a product obtained by these production methods by further performing a hydrogen thermal decomposition reaction using a catalyst. As another production method, there is a method of producing ethanol from sugarcane, bagasse, carbohydrate-based crops and the like by a biological treatment method, and further producing ethanol through ethylene oxide. It is also possible to adopt a method of producing by such a method and further purifying by a distillation operation or the like.

  Alternatively, as another method, a mixture of ethylene glycol and 1,2-propanediol is produced by converting biomass resources to glycerol, sorbitol, xylitol, glycol, fructose, cellulose, or the like, and further performing a hydrogenolysis reaction using a catalyst. I do. Alternatively, a method of producing ethanol from sugarcane, bagasse, carbohydrate crops, or the like by a biological treatment method, and further producing a mixture of ethylene glycol, diethylene glycol, and triethylene glycol via ethylene oxide may be used.

In the present invention, the bioconversion rate is defined as a value based on the ¹⁴ C concentration of radioactive carbon in circulating carbon as of 1950 in all the carbon atoms constituting polyethylene naphthalate (this value is set to 100%). Represents the ratio of the ¹⁴ C concentration. The concentration of ¹⁴ C as the radiocarbon can be measured by the following measurement method (radiocarbon concentration measurement). That is, the concentration of ¹⁴ C is measured by an accelerator mass spectrometry (AMS) in which a tandem accelerator and a mass spectrometer are combined, and isotopes of carbon (specifically, ¹² C and ¹³ C) contained in a sample to be analyzed. , ¹⁴ C) are physically separated by an accelerator using the weight difference between atoms, and the abundance of each isotope atom is measured.

In one mole of carbon atoms (6.02 × 10 ²³ ), there are about 6.02 × 10 ^{11 14} C, which is about one trillionth of a normal carbon atom. ¹⁴ C is called a radioisotope, and its half-life is regularly decreasing at 5730 years. It will take 2260 years to collapse. Therefore, fossil fuels such as coal, oil, and natural gas, which are considered to have passed 22.6 million years after carbon dioxide and other substances in the atmosphere were taken into plants and fixed, were initially immobilized. All of the ¹⁴ C elements contained in are decaying. Therefore, to date, fossil fuels such as coal, oil, and natural gas do not contain any ^14C element. Therefore, the chemical substances produced using these fossil fuels as raw materials also contain no ^14C element. On the other hand, ¹⁴ C undergoes a nuclear reaction in the atmosphere where cosmic rays undergo a nuclear reaction, is constantly generated, and the reduction due to radiation decay is balanced, and the amount of ¹⁴ C is constant in the earth's atmospheric environment.

On the other hand, if the carbon dioxide in the atmosphere has been immobilized incorporated such animals eat the plants and which in its captured state, ^{14 C} without newly replenished, half of ^{14 C} Over time, the ¹⁴ C concentration decreases at a constant rate over time. For this reason, by analyzing the ¹⁴ C concentration, it is possible to easily determine whether the material is a material using fossil resources or a compound using biomass resources. As the ^14C concentration, it is common practice to use the ^14C concentration in circulating carbon in nature in 1950 as a modern standard reference, and to use this ^14C concentration as a standard of 100%. At present, the ¹⁴ C concentration measured in this way is about 110 pMC (percent Modern Carbon), and plastics and the like used as samples are made of 100% natural (biological) substances. It is known that a value of about 110 pMC is exhibited if the value is obtained. This value corresponds to the above-mentioned bio-conversion rate of 100%. On the other hand, when this ¹⁴ C concentration is measured using a petroleum-based (fossil-based) substance, it shows almost 0 pMC. This value corresponds to the above-mentioned bio-conversion rate of 0%. Using these values, the mixture ratio of the naturally derived system-fossil derived system can be calculated. Further, as a modern standard reference serving as a reference for the ¹⁴ C concentration, it is preferable to use an oxalic acid standard issued by the NIST (National Institute of Standards and Technology). The specific activity of carbon in oxalic acid (activity intensity of ¹⁴ C per gram of carbon) is fractionated for each carbon isotope, corrected to a constant value for ¹³ C, and corrected for attenuation from 1950 AD to the measurement date Are used as standard ¹⁴ C concentration values.

The method for analyzing the concentration of ¹⁴ C in polyethylene naphthalate requires a pretreatment of polyethylene naphthalate first. Specifically, carbon contained in polyethylene naphthalate is oxidized and all converted to carbon dioxide. Further, the obtained carbon dioxide is separated from water and nitrogen, and the carbon dioxide is subjected to a reduction treatment to be converted into solid carbon, graphite. The obtained graphite is irradiated with cations such as Cs ⁺ to generate carbon negative ions. Subsequently, accelerated carbon ions using tandem accelerator, is charged converted from negative ions to positive ions, ¹² C ³⁺ by mass analysis electromagnet, ¹³ C ^3+, separating the progressive trajectory of ^{14 C 3+, 14} C ³⁺ Is measured by an electrostatic analyzer.

  In the present invention, polyethylene naphthalate produced by polymerization can be obtained by a production method using naphthalenedicarboxylic acid or a dialkyl ester of naphthalenedicarboxylic acid as a main raw material and using ethylene glycol as a diol component. Examples of the dialkyl ester of naphthalenedicarboxylic acid include lower dialkyl esters of naphthalenedicarboxylic acid, specifically, dimethyl ester, diethyl ester, dipropyl ester, dibutyl ester and the like.

  Here, "mainly" means that other acid components may be polymerized within a range that does not substantially impair the effects of the present invention. Examples of the copolymer component include a dicarboxylic acid component generally used in polyethylene naphthalate. Specific examples are preferably naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and lower alkyl esters thereof. Most of these are basically derived from fossil resources, and can be added up to 10% by weight together with other fossil resource-derived materials based on the total amount of the raw materials of the polyethylene naphthalate of the present invention.

  In the production of the polyethylene naphthalate of the present invention, if necessary, a small amount of additives such as a lubricant, an antioxidant, a solid-phase polymerization accelerator, a coloring agent, a fluorescent whitening agent, an antistatic agent, an antibacterial agent, and an ultraviolet ray. An absorbent, a light stabilizer, a heat stabilizer, a light-shielding agent or a matting agent may be added. However, these additives are also often derived from fossil resources, and may be added up to 10% by weight together with other fossil resource-derived materials, based on the total amount of the polyethylene naphthalate raw material of the present invention. it can.

  The above-mentioned polyethylene naphthalate can be produced by any method except that a raw material derived from a non-fossil raw material is used. Specifically, naphthalenedicarboxylic acid and a non-fossil raw material-derived ethylene glycol are directly subjected to an esterification reaction, or a dialkyl ester of a naphthalenedicarboxylic acid and a non-fossil raw material-derived ethylene glycol are subjected to a transesterification reaction, whereby naphthalenedicarboxylic acid A first-stage reaction for producing an ethylene glycol ester and / or a low-polymer thereof, and a polycondensation reaction of the first-stage reaction product by heating under reduced pressure in the presence of a polymerization reaction catalyst to a desired degree of polymerization. It can be produced by a second stage reaction.

In the polyethylene naphthalate of the present invention, the ratio to the total carbon in the repeating unit constituting polyethylene naphthalate obtained by using 2,6-naphthalenedicarboxylic acid or the like as a raw material as an acid component is 2,6-naphthalene. It is composed of 86% (12) of carbon derived from dicarboxylic acid and 14% (2) of carbon derived from ethylene glycol. The use of ethylene glycol having a biodegradation ratio of 80% or more as a diol component means that, among all carbons constituting the polyethylene naphthalate repeating unit, all carbons derived from ethylene glycol (all carbons constituting the polyethylene naphthalate repeating unit) (14% of them) are carbon atoms containing ¹⁴ C derived from non-fossil raw materials. Therefore, the theoretical calculation shows that the bioforming ratio of polyethylene naphthalate is 11% or more. It is one aspect of the present invention to employ such a polyethylene naphthalate having a bioconversion rate of 11% or more.
In order to exhibit the effects of the present invention described above, it is necessary that the polyethylene naphthalate has such a bio-conversion rate of 10% or more, and if it is less than 10%, the effect cannot be sufficiently exhibited.

  The intrinsic viscosity of the produced polyethylene naphthalate is preferably in the range of 0.50 to 1.00 dL / g. If the intrinsic viscosity is less than 0.50 dL / g, the strength of the obtained molded article becomes extremely weak, and it is difficult to use the molded article. On the other hand, if the intrinsic viscosity exceeds 1.00 dL / g, the melt viscosity becomes too large, and the moldability is extremely deteriorated. The intrinsic viscosity is preferably in the range of 0.60 to 0.70 dL / g. The intrinsic viscosity can be calculated from the solution viscosity in which polyethylene naphthalate is dissolved, as described later.

  Generally, in the polymerization reaction of polyethylene naphthalate, a transesterification catalyst and a polymerization reaction catalyst are used, and heavy metals such as manganese, antimony, and germanium are mainly used. More specifically, manganese acetate, antimony trioxide, germanium dioxide and the like can be mentioned. Since heavy metals have a large environmental load, it is more desirable in the present invention to use a titanium catalyst having a relatively low environmental load as both reaction catalysts. Use of polyethylene naphthalate as an acid component, ethylene glycol derived from a non-fossil raw material as a diol component, and use of a titanium catalyst as a polymerization reaction catalyst to provide a belt reinforcing material containing polyethylene naphthalate that can further improve global environmental problems. Becomes possible.

  As for the titanium catalyst used as the polymerization reaction catalyst, a compound represented by the following general formula (I), or a compound represented by the following general formula (I) and 2,6-naphthalenedicarboxylic acid represented by the following general formula (II) or It is preferable to use a product obtained by reacting the anhydride with the anhydride.

［但し、式（Ｉ）中、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４はそれぞれ同一もしくは異なって、アルキル基またはフェニル基を表す。ｍは１〜４の整数を表し、且つｍが２〜４のとき、それぞれ２〜４個あるＲ^２およびＲ^３はそれぞれ同一の基または異なる基を表す。］

[However, in the formula (I), R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents an alkyl group or a phenyl group. m represents an integer of 1 to 4, and when m is 2 to 4, 2 to 4 R ² and R ³ each represent the same group or different groups. ]

  Examples of the titanium compound represented by the above formula (I) include titanium tetraalkoxides such as titanium tetraethoxide, titanium tetraisopropoxide, titanium tetra-n-propoxide and titanium tetrabutoxide, and titanium tetraphenoxide. , Hexaethyl dititanate, hexapropyl dititanate, hexabutyl dititanate, hexaphenyl dititanate, octaethyl trititanate, octapropyl trititanate, octabutyl trititanate, octaphenyl trititanate and the like. As the aromatic polycarboxylic acid represented by the general formula (II) or an anhydride thereof, phthalic acid, trimellitic acid, hemi-mellitic acid, pyromellitic acid and anhydrides thereof are preferably used.

  When reacting the above titanium compound with 2,6-naphthalenedicarboxylic acid or its anhydride, part or all of 2,6-naphthalenedicarboxylic acid or its anhydride is dissolved in a solvent, and titanium It is carried out by adding the compound dropwise and heating at a temperature of 0 to 200 ° C for at least 30 minutes, preferably at a temperature of 30 to 150 ° C for 40 to 90 minutes. The reaction pressure at this time is not particularly limited, and normal pressure is sufficient. As a solvent for dissolving 2,6-naphthalenedicarboxylic acid or its anhydride, any of ethanol, ethylene glycol, trimethylene glycol, tetramethylene glycol, benzene and xylene can be used as desired.

  Here, the reaction molar ratio of the titanium compound to 2,6-naphthalenedicarboxylic acid or its anhydride is not particularly limited, but if the ratio of the titanium compound is too high, the polyethylene mole obtained by using this compound as a catalyst may be used. The color tone of phthalate may deteriorate or the softening point may decrease. Conversely, if the proportion of the titanium compound is too low, the polycondensation reaction may not easily proceed in the polyethylene naphthalate production process. Therefore, the reaction molar ratio of the titanium compound to 2,6-naphthalenedicarboxylic acid or its anhydride is preferably in the range of 2/1 to 2/5. Particularly preferably, it is 2/2 to 2/4.

  It is preferable that the amount of the titanium element soluble in polyethylene naphthalate contained in the polyethylene naphthalate of the present invention is in the range of 5 to 70 ppm based on all dicarboxylic acid components. Here, the titanium element soluble in polyethylene naphthalate is included in polyethylene naphthalate as inorganic particles such as titanium dioxide, and the Ti element present in polyethylene naphthalate without being mixed with polyethylene naphthalate at the molecular level does not apply. Means that. More specifically, a titanium element contained in an organic Ti-based catalyst or the like corresponds to a polyethylene naphthalate-soluble titanium element. More specifically, the polyethylene naphthalate-soluble titanium element does not include an inorganic titanium compound such as titanium dioxide added for the purpose of matting, and includes an organic titanium compound and matting usually used as a catalyst. Refers to organic titanium compounds contained as impurities in titanium dioxide used as an agent. If the amount of the titanium element soluble in polyethylene naphthalate is less than 5 ppm, the polycondensation reaction becomes slow, and if it exceeds 70 ppm, the color tone of the obtained polyethylene naphthalate may be poor and its heat resistance may be reduced. Not preferred. The amount of titanium element is preferably in the range of 7 to 60 ppm, more preferably 10 to 50 ppm, based on polyethylene naphthalate.

  When producing the polyethylene naphthalate of the present invention, any phosphorus compound can be added in addition to the transesterification catalyst and the polycondensation catalyst. The type of the phosphorus compound is not particularly limited. For example, when a titanium-based catalyst is used, it is preferable to add the phosphorus compound represented by the following general formula (III) at an arbitrary stage.

［上記式中、Ｒ^６およびＲ^７は同一または異なっている、炭素原子数１〜４個のアルキル基を表し、Ｘは−ＣＨ_２−または−ＣＨＰｈ−を表す。］

[In the above formula, R ⁶ and R ⁷ are the same or different and represent an alkyl group having 1 to 4 carbon atoms, and X represents —CH ₂ — or —CHPh—. ]

  Examples of the phosphorus compound (phosphonate compound) of the general formula (III) include carbomethoxymethanephosphonic acid, carbethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carboptoxymethanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, It is preferably selected from the dimethyl, diethyl, dipropyl and dibutyl esters of ethoxy-phosphono-phenylacetic acid, carboxy-phosphono-phenylacetic acid and carboxy-phosphono-phenylacetic acid. More preferred among these compounds are carbomethoxymethane phosphonic acid, carbomethoxymethane phosphonic acid dimethyl ester, carbomethoxymethane phosphonic acid diethyl ester, carboethoxymethane phosphonic acid, carboethoxymethane phosphonic acid dimethyl ester or carboethoxymethane This is diethyl phosphonate. The above-mentioned phosphonate compound, the reaction with the titanium compound proceeds relatively slowly as compared with the phosphorus compound which is usually used as a stabilizer, so that the catalytic activity duration of the titanium compound during the reaction becomes longer, and as a result, The amount of the titanium compound added to polyethylene naphthalate can be reduced.

Further, it is preferable that the catalyst system containing the above-mentioned titanium compound simultaneously satisfies the following mathematical expressions (1) and (2).
0.65 ≦ P / Ti ≦ 5.0 (1)
10 ≦ P + Ti ≦ 200 (2)
[In the above formulas (1) and (2), Ti represents the concentration (weight ppm) of a titanium metal element soluble in polyethylene naphthalate contained in polyethylene naphthalate, and P represents phosphorus contained in polyethylene naphthalate. It represents the concentration of elemental phosphorus (ppm by weight) in the compound. ]

  Here, when (P / Ti) is less than 0.65, the hue of polyethylene naphthalate is yellowish, which is not preferable. On the other hand, when (P / Ti) exceeds 5.0, the polymerization reactivity of polyethylene naphthalate is greatly reduced, and it is difficult to obtain the desired polyethylene naphthalate. Although the proper range of (P / Ti) is characteristically narrower than that of a normal metal catalyst system, when it is in the proper range, an effect which has not existed in the past as in the present invention can be obtained. On the other hand, when (Ti + P) is less than 10, productivity in the spinning process is greatly reduced, and satisfactory performance cannot be obtained. On the other hand, when (Ti + P) is more than 200, a small amount of foreign matters due to the catalyst is generated, which is not preferable. The range of the above formulas (1) and (2) is preferably (P / Ti) in the range of 1.0 to 4.5 in the formula (1), and (Ti + P) in the range of 12 to 150 in the formula (2). (P / Ti) in the formula (1) is more preferably in the range of 2.0 to 4.0, and (Ti + P) in the formula (2) is more preferably in the range of 15 to 100. In the production method of the present invention, the polymerization reaction carried out using the catalyst system is carried out at a temperature of 230 to 320 ° C. under normal pressure or reduced pressure, preferably at 0.05 Pa to 0.2 MPa, by combining these conditions. It is preferable to carry out the polymerization reaction for 15 to 300 minutes.

The polyethylene naphthalate obtained according to the present invention can substantially reduce the amount of carbon dioxide generated when finally burned. As mentioned above, plants absorb carbon dioxide in the air during their growth and fix themselves to themselves by photosynthesis, so they use plastics produced from the plant and are burned after use. Carbon dioxide is the same amount as the carbon dioxide originally absorbed by the plant, is carbon neutral, and can be considered to not substantially increase carbon dioxide on earth even if burned. The amount of carbon dioxide generated during complete combustion can be obtained by calculation. For example, in the case of polyethylene naphthalate (PEN), when one constituent unit (molecular weight: 242.2) of PEN is completely burned, 14 times molar amount of CO ₂ (molecular weight: 44.0) is generated. The amount is determined by the following equation (3).
Carbon dioxide generation CO ₂ (g)
= Weight of PEN burned (g) /242.2×14×44 (3)

However, if ethylene glycol is derived from biomass, the amount of carbon dioxide generated can be obtained by the following formula (4), as in the case of PEN.
Carbon dioxide generation CO ₂ (g)
= Weight of PEN burned (g) /242.2×12×44 (4)

  Therefore, by using biomass ethylene glycol, a substantial carbon dioxide emission can be suppressed by 300 g or more per 1 kg of polyethylene naphthalate as compared with conventional polyethylene naphthalate.

Further, in the present invention, it is necessary that at least 20% by weight of the total amount of the components constituting the polyethylene naphthalate is composed of a non-fossil raw material. As described above, the non-fossil raw material refers to an organic compound that is a raw material produced from biomass resources as a non-fossil raw material. As a result of the study by the present inventors, the effect of the present invention described above can be obtained by employing polyethylene naphthalate in which the composition ratio of the non-fossil raw material in such polyethylene naphthalate is 20% by weight or more, If the amount is less than 20% by weight, the effect cannot be sufficiently exhibited. As an example, as described above, when the polymer is polyethylene naphthalate (PEN) and the ethylene glycol is derived from biomass, a non-fossil raw material in polyethylene naphthalate is similarly used as shown in the following formula (5). The configured weight ratio can be calculated.
Molecular weight of EG moiety in PEN1 structural unit / molecular weight of PEN1 structural unit = 60 / 242.2 × 100 = 24.8% (5)

  Therefore, it is preferable that 24% by weight or more of the total amount constituting polyethylene naphthalate is constituted by non-fossil raw materials. By satisfying these requirements, the polyethylene naphthalate of the present invention can achieve a substantial reduction in carbon dioxide generation.

  As described above, according to the present invention, the amount of carbon dioxide generated when the polyethylene naphthalate is burned is reduced as compared with the same using a fossil raw material. Belt reinforcement is obtained.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

  Tires and tire members were produced using polyethylene naphthalate (PEN) produced using conventional fossil raw materials and non-fossil raw materials, and performance tests were performed.

各測定方法は以下の通りである。

Each measuring method is as follows.

-Bioconversion rate: Based on ASTM D6866 Method B, after measuring the concentration of ¹⁴ C contained in the code, based on the concentration of ¹⁴ C, which is radioactive carbon in circulating carbon as of 1950 (this value is set to 100%) ) And the ratio of ¹⁴ C concentration.

-Number from above: Measure the number from above according to JIS L1017.

-Cord diameter: Measure the cord diameter according to JIS L1017.

-Fineness: Measures the positive fineness according to JIS L1017.

-Strong: A tensile test is performed according to JIS L1017, and the load when the cord breaks is measured.

Cut and elongation: A tensile test is performed in accordance with JIS L1017, and the elongation percentage when the cord breaks is measured.

EASL @ 2cN / dtex: A tensile test is performed in accordance with JIS L1017, and the elongation at 2cN / dtex is measured.

Dry heat shrinkage: Shrinkage was measured by the change in cord length when heated under no load, in accordance with JIS L1017 B method.

-T-pull adhesion: A pull-out test is performed according to JIS L1017, and the pull-out adhesive strength is measured.

Disc fatigue: According to JIS L1017, after the cord is fatigued with a GCF fatigue tester, the strength of the cord is measured to determine the strength retention. Compression / elongation strain = 10% / 5%, fatigue time: 24 hours

-General durability: The cord taken out of the tire after the end of the JIS D4230-A method was measured for cord strength in accordance with JIS L1017. The strength retention is determined by dividing the obtained cord strength by the strength of the cord taken out of the new tire.

-High-speed durability: Evaluated with an upper limit of speed range +30 km / hr. × 10 min under ECS-30 test conditions. Dismantle after the end. The cord taken from the tire is measured for cord strength in accordance with JIS L1017. The strength retention is determined by dividing the obtained cord strength by the strength of the cord taken out of the new tire.

-Driving stability Dry / Wet: Tested on a test course owned by Toyo Tire & Rubber Co., Ltd.
The vehicle used for the test is a vehicle that uses the tires as standard.
Sensory evaluation by three test drivers. Average value of perfect score = 5 points / standard = 3 points.
Dry is adjusted to a dry road, and Wet is adjusted to a depth of 1 mm. The runway is different.

As is clear from the table, the performance of the pneumatic tire manufactured from polyethylene naphthalate using the raw material derived from the non-fossil raw material of the present invention and the performance of members constituting the same are the same as those using the conventional raw material derived from fossil raw material. It was shown that there is.
Therefore, according to the present invention, it is possible to provide an environmental load reduction type belt reinforcing material.

Claims (3)

  A pneumatic tire using polyethylene naphthalate manufactured using a raw material derived from a non-fossil raw material as a belt reinforcing material.   2. The pneumatic tire according to claim 1, wherein a polyethylene naphthalate in which a linear portion or a cyclic portion of the polyethylene naphthalate is produced using a raw material derived from a non-fossil raw material is used as a belt reinforcing material.   2. The pneumatic tire according to claim 1, wherein a polyethylene naphthalate produced by using a raw material derived from a non-fossil raw material is used as a belt reinforcing material in a linear part and a cyclic part of the polyethylene naphthalate.