JP2010180348A - Method for producing ultra-flexible polyurethane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an ultra-flexible polyurethane having a long pot life and a short curing rate, and affording a lightweight cast cured product having excellent energy absorbency without stickiness so as to cause blocking after hot-curing. <P>SOLUTION: There is provided the method for producing the ultra-flexible polyurethane having 20-80 Shore 00 hardness, 0.65-0.85 density, and ≥0.3 tanδ of a molded product after the hot-curing. The method for production includes: (A) a preparing step of adding a filler having 0.035-0.050 density, a curing catalyst, a cocatalyst and a dehydrating agent to a polyol, and preparing a polyol component having ≤550 ppm moisture content, wherein the amount of the formulated filler is ≥1.0 mass% based on the total mass of the polyol and filler; (B) a mixing step of mixing the polyol component with an isocyanate component under uniform mixing conditions; and (C) a curing step of casting the mixture prepared in the (B) into a mold, hot-curing the mold, and producing the ultra-flexible polyurethane. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing an ultra-soft polyurethane, and in particular, has a long pot life and a short curing speed, is excellent in energy absorption after heat curing, has no stickiness to block, and is lightweight. It is related with the manufacturing method of the super soft polyurethane used as the molded article which is.

When a flexible polyurethane is produced by the one-shot method, it is usually carried out by mixing and agitating a liquid mixture consisting of polyol, isocyanate, filler, plasticizer, antioxidant and weathering agent, pouring it into a mold and thermosetting it. As a result, a desired molded product is obtained.
Soft polyurethane is excellent in energy absorption, shock absorption use (inner soles of shoes, helmet cushions, protectors such as elbows, cushioning materials during transportation, etc.), vibration absorption use (
Precision parts protection, testing machines, vibration isolation for precision equipment, vibration isolation for heavy equipment, etc.), pressure dispersion (
Suitable for chairs, beds, rugs such as cushions, and body pressure such as pillows).

For example, Japanese Patent Publication No. 62-26330 discloses poly (1.2-propylene glycol) and N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine. A process for the production of polyurethane elastomers, which comprises reacting less than a stoichiometric amount with at least one aromatic isocyanate.
However, since this urethane elastomer exhibits temperature-dependent energy absorption (impact damping), it has been proposed in JP-A-61-19618 to add a monohydric alcohol component to improve it. It was.
However, since this urethane elastomer is also sticky, JP-A-6-73150 discloses that polyoxypropylene polyol having a molecular weight of 1000 to 6000 is 90 to 65 wt%, low molecular weight polyhydric alcohol having a molecular weight of 60 to 700 and 10 to 35 wt% and polyisocyanate. And a method for producing a polyurethane elastomer comprising reacting 0.15-0.5 monohydric alcohol having 10 or less carbon atoms in an equivalent ratio with respect to the total amount of polyol at an OH / NCO ratio of 1.0. Has been.
As a method for improving the heat resistance of a flexible polyurethane elastomer, in Japanese Patent Application Laid-Open No. 60-67524, an NCO / OH equivalent ratio is 0.4 to 0.95 when a trifunctional polyether polyol based on glycerin is reacted with a polyisocyanate. A method for producing a flexible polyurethane elastomer is also proposed.

Japanese Examined Patent Publication No. 62-26330 Japanese Patent Laid-Open No. 61-19618 JP-A-6-73150 JP 60-67524 A

The present invention has a long pot life and a short curing speed, and after heat curing, is an ultra-soft polyurethane that becomes a cast cured product that is excellent in energy absorption, does not have stickiness to block, and is light, i.e. In terms of specific performance evaluation, the molded product after heat curing has a Shore 00 hardness of 20 to 80, a density of 0.65 to 0.85 and a tan δ of 0.3 or more. Offering is an issue.

The characteristics required in applications where soft polyurethane is used are not only sticky enough to block, but also light weight except in special cases, as well as viscoelastic bodies with energy absorption. Is required.
The addition of organic microballoons to the polyol component was studied so that the above required characteristics could be satisfied. However, due to a large difference in specific gravity from the polyol, it floats and separates in an extremely short time. However, it has been found that moisture is easily mixed by the air entrainment generated at this time.
When water is mixed, if a lead-based catalyst that is not easily affected by moisture is used, the water-based deactivation is hardly used, but the lead-based catalyst tends not to be used from the viewpoint of environmental influences. It has been found that the use of an affected catalyst is likely to cause a slow curing rate and foaming due to catalyst deactivation, which is a very negative factor.
In particular, a flexible polyurethane generally has a lower NCO / OH equivalent ratio, so that the curing is slower than a normal polyurethane. Therefore, the influence of the moisture causes the curing to be further delayed, and in some cases, production is impossible.
In the above case, when a moisture content is adjusted to a specific range by adding a dehydrating agent to the polyol component, even if a catalyst affected by moisture is used, it does not cause a curing rate delay due to catalyst deactivation. I found out.

  As a result of further investigation based on the above findings, the present inventors have added a specific amount of filler, curing catalyst, co-catalyst and dehydrating agent having a specific range of density to the polyol, so that the water content is 550 ppm or less. When the polyol component is prepared, the polyol component is mixed with the isocyanate component under uniform mixing conditions, the resulting mixture is poured into a mold, and heated and cured, even if the curing catalyst is not a lead-based catalyst. Satisfying the required pot life and curing rate, that is, having a long pot life and a short curing rate, and after heat curing, it is excellent in energy absorption, is not sticky enough to block and is lightweight. The present invention was completed by finding a cast-cured product of ultra-soft polyurethane.

That is, the present invention
(1) A method for producing an ultra-soft polyurethane having a Shore 00 hardness of 20 to 80, a density of 0.65 to 0.85, and a tan δ of 0.3 or more of the molded product after heat curing,
A) A polyol component having a moisture content of 550 ppm or less is prepared by adding a filler having a density of 0.035 to 0.050 to the polyol, a curing catalyst, a co-catalyst and a dehydrating agent. In this case, the blending amount of the filler is A preparation step of 1.0% by weight or more based on the total weight of polyol and filler;
B) a mixing step of mixing the polyol component with an isocyanate component under uniform mixing conditions;
C) A production method including a curing step of casting the mixture obtained in B) into a mold and heat-curing to produce the ultra-soft polyurethane,
(2) The production method according to the above (1), wherein the filler is an organic microballoon having a particle size of 40 to 60 μm made of a polyvinylidene chloride-based copolymer.
(3) The method according to (1) or (2), wherein the curing catalyst is bismuth octylate,
(4) The production method according to any one of (1) to (3), wherein the dehydrating agent is synthetic zeolite.
(5) In the preparation step, the production method according to any one of (1) to (4), wherein the moisture content of the polyol component is 300 ppm or less by adding a dehydrating agent,
(6) The production method according to any one of (1) to (5), wherein uniform mixing of the polyol component is performed by pipeline circulation in which the polyol component is circulated in an endless pipeline.
(7) In the curing step, a cast cured product having a pot life of 2 minutes or longer, capable of demolding within 10 minutes and reaching the final hardness within 60 minutes is obtained ( 1) The production method according to any one of (6),
It is about.
In the present specification, the ultra-soft polyurethane means a polyurethane having a Shore 00 hardness of 20 to 80 in the molded product after heat curing.

According to the present invention, an ultra-soft polyurethane that has a long pot life and a short curing speed, is excellent in energy absorption after heat curing, has no stickiness to block, and is a light-weight cast cured product. A manufacturing method is provided.
The present invention suppresses the floating separation of the filler even when a filler having a low density such as an organic microballoon is used. Furthermore, there is also an effect of suppressing stickiness.
In addition, the present invention achieves a long pot life and a short curing speed even when a bismuth-based catalyst, for example, a bismuth-based catalyst is used, by setting the moisture content in the system to a specific range or less. Can be said to be an excellent method from the viewpoint of environmental protection.

It is a graph which shows the correlation of Shore 00 hardness and tan-delta. It is a graph which shows the correlation of the density of a microballoon, and its destruction rate (after pipeline circulation 72 hours using a 0.3MPa diaphragm pump). It is a graph which shows the correlation of the moisture content (ppm) of a polyol component, and the mold release possible time (minutes) of a cast hardening product.

The present invention will be described in more detail.
The method for producing the ultra-soft polyurethane of the present invention comprises:
A) A polyol component having a moisture content of 550 ppm or less is prepared by adding a filler having a density of 0.035 to 0.050 to the polyol, a curing catalyst, a co-catalyst and a dehydrating agent. In this case, the blending amount of the filler is A preparation step of 1.0% by weight or more based on the total weight of polyol and filler;
B) a mixing step of mixing the polyol component with an isocyanate component under uniform mixing conditions;
C) The mixture obtained in B) is poured into a mold and cured by heating to produce the ultra-soft polyurethane.

The polyol that can be used in the step A) of the present invention is not particularly limited as long as it is a polyol (polyol compound) that can be used for producing a flexible polyurethane. For example, the compound as shown below The polyol can be used.
(1) A blend of poly (1,2-propylene glycol) having an average molecular weight of 2000 and N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine.

(2) 90-65% by mass of polyoxypropylene polyol having an average molecular weight of 1000-6000, 10-35% by mass of low molecular weight polyhydric alcohol having an average molecular weight of 60-700, and 0.15% of monohydric alcohol having 10 or less carbon atoms. 0.5 (Equivalent ratio to propylene polyol: monohydric alcohol increases aliphatic primary alcohol having 10 or less carbon atoms, such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc. And alkyl ether alcohols can also be used).

(3) Poly (1,2-propylene glycol) having an average molecular weight of 1500 to 2500, 90 to 65 wt%, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 10 to 35 wt%, and carbon number 3 to 10 monohydric alcohol 0.15 to 0.5 (equivalent ratio to the total amount of propylene polyol: monohydric alcohol is an aliphatic primary alcohol having 10 or less carbon atoms, for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl Alcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc. Alkyl ether alcohol can also be used).

(4) 2 to 8 functional polyether polyols having an average molecular weight of 400 to 6000, such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butylene glycol, dihydroxydiphenylpropane, glycerin, hexanetriol, and trimethylolpropane. , Pentaerythritol, sorbitol, sucrose, dipropylene glycol, dihydroxydiphenylmethane, dihydroxydiphenyl ether, dihydroxybiphenyl, hydroquinone, resorcin, naphthalenediol, aminophenol, aminonaphthol, phenol formaldehyde condensate, phloroglucin, methyldiethanolamine, ethyldiisopropanolamine, tri Ethanolamine, ethylenediamine, hexa Polyether polyol obtained by adding one or more of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. to tylenediamine, bis (p-aminocyclohexane), tolylenediamine, diphenylmethanediamine, naphthalenediamine, or the like, or Polyester polyols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,3- or 1,4-butylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, decamethylene glycol, bisphenol A, bisphenol F, p-xylylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, glyce One or more of ethylene oxide, propylene oxide, butylene oxide, styrene oxide adducts such as ethylene, trimethylolpropane, hexanetriol, pentaerythritol, etc., and malonic acid, maleic acid, succinic acid, adipic acid, glutaric acid , Polyester polyols from one or more of pimelic acid, sebacic acid, oxalic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid and the like, or cyclic esters such as propiolactone, butyrolactone, caprolactone A polyol obtained by ring-opening polymerization of a polyester, a polyester polyol produced from the above polyol and a cyclic ester, a polyester polyol produced from 3 types of the above polyol, dibasic acid and cyclic ester, or a 1,2-polybutadiene polymer. Riol, 1,4-polybutadiene polyol, polychloroprene polyol, butadiene-acrylonitrile copolymer polyol, polydimethylsiloxane dicarbinol, polytetramethylene ether glycol and ricinoleic acid ester such as castor oil, the aforementioned polyether polyol, polyester A polymer polyol obtained by graft polymerization of an ethylenically unsaturated compound such as acrylonitrile, styrene or methyl methacrylate to a polyol.

(4) (a) Functionality in the range 2 to 6, preferably in the range 2-3, having a primary hydroxyl group at the end and having a molecular weight in the range 2500-8000, preferably in the range 2500-4000. (B) polyhydric alcohols such as glycerin, 1,4-butanediol, pentaerythritol, trimethylolpropane, 1,2-propylene glycol, 1,6-hexanediol, 2-ethylhexane-1 , 3-diol, hydroquinone bis (hydroxyethyl ether), 1,1 ′, 1 ″, 1 ′ ″-ethylenedinitrilotetra- (2-propanol), and (c) having 10 or fewer carbon atoms Aliphatic 1
Blends with monovalent alcohols, preferably alcohols having from 1 to 6 carbon atoms, from methyl alcohol to n-hexanol.

  Preferred polyols (polyol blends) include (2) 90 to 65 mass% of polyoxypropylene polyol having an average molecular weight of 1000 to 6000, 10 to 35 mass% of low molecular weight polyhydric alcohol having an average molecular weight of 60 to 700, and carbon number. 10 or less monohydric alcohol 0.15 to 0.5 (equivalent ratio to propylene polyol: monohydric alcohol is an aliphatic primary alcohol having 10 or less carbon atoms, such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, And hexyl alcohol, 2-ethylhexyl alcohol, etc. Alkyl ether alcohol can also be used.

More preferred polyols (polyol blends) include (3) 90-65 wt% poly (1,2-propylene glycol) having an average molecular weight of 1500-2500, and N, N, N ′.
, N′-tetrakis (2-hydroxypropyl) ethylenediamine 10-35 wt%,
C3-C10 monohydric alcohol 0.15-0.5 (equivalent ratio to the total amount of propylene polyol: monohydric alcohol is an aliphatic primary alcohol having 10 or less carbon atoms such as methyl alcohol, ethyl alcohol, propyl alcohol , Butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc. Alkyl ether alcohol can also be used.

As the filler that can be used in the step A) of the present invention, for example, an organic microballoon can be used. As the organic microballoon, for example, an organic microballoon made of a polyvinylidene chloride-based copolymer is used. It is preferred to use.
The filler has a density of 0.035 to 0.050 and is used in an amount of 1.0% by weight or more based on the total weight of polyol and filler.
If the density is less than 0.035, the balloon breaking rate is increased during uniform mixing, for example, during pipeline circulation, and as a result, the density of the molded product is improved.
Moreover, when the amount of the filler is less than 1.0% by mass, the density of the molded product is increased and blocking (stickiness) is generated, which is not preferable.
The particle size of the filler is preferably in the range of 40 to 60 μm.

As the curing catalyst that can be used in step A) of the present invention, various metal catalysts such as lead, tin, cobalt, and bismuth that are used for ordinary polyurethane production are considered.
However, the use of a catalyst that is problematic in terms of environmental pollution such as a lead-based catalyst is not preferable. For this reason, for example, the use of a bismuth-based catalyst that does not cause a problem in terms of environmental pollution is preferable.
As the bismuth catalyst, for example, bismuth octylate is preferable.
The amount of the catalyst used is in the range of 0.01 to 0.5 parts by mass, preferably 0.01 to 0.20 parts by mass with respect to 100 parts by mass of the total mass of polyol and filler.
If it is less than 0.01 parts by mass, the post-curing catalytic effect is insufficient, and if it exceeds 0.5 parts by mass, the physical properties of the ultra-soft polyurethane are deteriorated.

Cocatalysts that can be used in step A) of the present invention include, for example, carboxylic acids, and preferably octylic acid.
The amount of the cocatalyst used is in the range of 0.1 to 3.0 parts by mass, preferably 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the total mass of polyol and filler.

In step A) of the present invention, the moisture content of the prepared polyol component is adjusted to 550 ppm or less by adding a dehydrating agent.
As the dehydrating agent, a commonly used dehydrating agent can be used. For example, a synthetic zeolite powder, preferably a molecular sieve of powder (for example, 3A) can be used.
When the dehydrating agent is added, if the water content of the polyol component exceeds 550 ppm, the demoldable time exceeds 10 minutes, which is not preferable.
The moisture content is preferably 300 ppm or less.
As described above, the amount of the dehydrating agent used is an amount that allows the moisture content of the polyol component to be 550 ppm or less, but usually 0.3 to 5 parts by mass with respect to 100 parts by mass of the total mass of the polyol and filler. The range is preferably 0.5 to 3 parts by mass.
If it is less than 0.3 parts by mass, it is difficult to make the moisture content 550 ppm or less, and if it exceeds 5 parts by mass, the mechanical strength decreases, which is not preferable.
The dehydrating agent can be added to the mixture of the polyol and the filler at the time of stirring for eliminating sedimentation and floating of the filler that occurs when the curing catalyst and the cocatalyst are added. It is also possible to add a dehydrating agent to the mixture composed of the agent, and then add a curing catalyst and a co-catalyst, and stir and degas to eliminate sedimentation and floating of the filler.

The polyol component prepared above is mixed with the isocyanate component while uniformly mixing so that the filler does not settle and float.
The uniform mixing is not particularly limited as long as the filler does not settle and float, but pipeline circulation in which the filler is circulated in an endless pipeline is preferable.
The pipeline circulation can be performed using a diaphragm pump, for example, a 0.3 MPa diaphragm pump.

  Examples of isocyanate components that can be used in step B) of the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and mixtures thereof (TDI), diphenylmethane-4,4′-diisocyanate (MDI). ), Naphthalene-1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-biphenylene diisocyanate (TODI), xylylene diisocyanate (XDI), dicyclohexylmethane-4,4′-diisocyanate (hydrogenated) MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), hydrogenated xylylene diisocyanate (HXDI), crude TDI, polymethylene polyphenyl isocyanate (crude MDI), and isoforms of these isocyanates Cyanurate modified products, carbodiimide-modified products, biuret modified products thereof.

The isocyanate component can be used alone or as a mixture of two or more.
The amount of the isocyanate component used is such that the equivalent ratio of the amount of NCO groups contained in the isocyanate component to the total amount of OH groups contained in the polyol (NCO / OH equivalent ratio) is 0.4 to 1.4. The range is preferably 0.5 to 1.2, and more preferably 0.6 to 1.0.

The mixture obtained above is poured into a mold and heat-cured, so that the cast-cured product after heat-curing has a Shore 00 hardness of 20 to 80, a density of 0.65 to 0.85 and a tan δ of 0.00. An ultra-soft polyurethane having 3 or more is produced.
A normal method can be used for casting into the mold, but it is preferable to cast into the mold by measuring and discharging with a dispenser.
Moreover, although normal hardening conditions can be used for heat hardening, it is preferable to heat-harden at 60 to 80 degreeC.
The cast-cured product obtained by the above heat curing has a pot life of 2 minutes or more, becomes demoldable within 10 minutes, and reaches the final hardness within 60 minutes.

In the present invention, in addition to the above components, a filler (a normally used inorganic filler,
Other additives well known in the art, such as, for example, calcium carbonate, glass fibers, etc.), plasticizers (usually used like DOP), stabilizers, etc. can also be added.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to an Example.
Example 1
A polyol containing 2 parts by mass of a microballoon (particle size: 40-60 μm, density: 0.043) made by Matsumoto Yushi Co., Ltd., which is made of a copolymer mainly composed of polyvinylidene chloride, which is a filler as a lightening agent. Polyol for viscoelastic polyurethane A-013 (average hydroxyl value 86.8) (catalyst-free product): manufactured by Mitsui Chemicals Co., Ltd. 100 parts by mass (the amount used as a polyol is 98 parts by mass) Stirred to re-disperse the balloon, and added 0.05 parts by mass of bismuth octylate (Bucat 25: manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst and 0.30 parts by mass of octylic acid as a co-catalyst Further, 0.50 parts by mass of a dehydrating agent (Molecular Sieve 3A: Union Showa Co., Ltd.) was added and stirred. Table 1 shows the water content of the mixture after adding and stirring the dehydrating agent.
The mixture then circulated through the pipeline to prevent re-agglomeration, and in a dispenser, the isocyanate (carbodiimide-modified MDI Cosmonate LK (NCO% 28.3): manufactured by Mitsui Chemicals) 17 0.05 parts by mass (NCO / OH equivalent ratio = 0.74), and poured into a mold, heated to 70 ° C. to accelerate curing, possible demolding time, final hardness arrival time, final hardness, blocking Presence / absence, density and tan δ were measured.
The measurement results are shown in Table 1.
In addition, the cast-cured product manufactured in Example 1 is a typical example in the case of Shore 00 hardness of 30 degrees, which is extremely soft.

In addition, the “demolding time” in the table is the time (minutes) required to reach a hardness of 70% of the final hardness, which is not deformed by the stress at the time of removal and does not adhere to the silicon release paper. "Presence / absence of blocking" indicates whether or not there is structural collapse when the molded product is stacked, left in an oven at 50 ° C for 24 hours, removed, and peeled off after cooling. Also, tan δ in the table represents the result measured under the following measurement conditions.
Apparatus: SOLID ANALYZER RSA II (manufactured by TA Instruments)
Deformation mode: Compression vibration mode: 30 Hz
Measurement temperature: 25 ° C

Example 2
The same operation and measurement as in Example 1 except that the amount of isocyanate (carbodiimide-modified MDI Cosmonate LK: manufactured by Mitsui Chemicals, Inc.) was changed to 18.5 parts by mass (NCO / OH equivalent ratio = 0.81). Table 1 shows the measurement results.
In addition, the cast cured product manufactured in Example 2 is a typical example in the case of Shore 00 hardness of 50 degrees.

Example 3
The same operation and measurement as in Example 1 except that the amount of isocyanate (carbodiimide-modified MDI Cosmonate LK: manufactured by Mitsui Chemicals, Inc.) was changed to 20.5 parts by mass (NCO / OH equivalent ratio = 0.90). Table 1 shows the measurement results.
In addition, the cast cured product manufactured in Example 3 is a typical example in the case of Shore 00 hardness of 70 degrees.

Example 4
The same operation and measurement as in Example 1 were performed except that the amount of the dehydrating agent (Molecular Sieve 3A: manufactured by Union Showa Co., Ltd.) was changed to 1.5 parts by mass, and each measurement result is shown in Table 1.

Example 5
The amount of filler (microballoon made of a copolymer mainly composed of polyvinylidene chloride, particle size 40-60 μm, density 0.043: manufactured by Matsumoto Yushi Co., Ltd.) was changed to 1.4 parts by mass, and polyol ( Polyol for viscoelastic polyurethane A-013 (catalyst-free product): Mitsui Chemicals Co., Ltd.) was used in an amount of 98.5 parts by mass, and dehydrating agent (Molecular Sieve 3A: Union Showa Co., Ltd.) was used. The same operation and measurement as in Example 1 were performed except that the amount was changed to 1.0 part by mass, and each measurement result is shown in Table 1.

Example 6
The amount of filler used (microballoon made of a copolymer mainly composed of polyvinylidene chloride, particle size 40-60 μm, density 0.043: manufactured by Matsumoto Yushi Co., Ltd.) was changed to 2.8 parts by mass, and polyol ( Viscoelastic polyurethane polyol A-013 (catalyst-free product): Mitsui Chemicals Co., Ltd.) was used in an amount of 97.2 parts by mass, and dehydrating agent (Molecular Sieve 3A: Union Showa Co., Ltd.) was used. The same operation and measurement as in Example 1 were performed except that the amount was changed to 1.0 part by mass, and each measurement result is shown in Table 1.

Comparative Example 1
The same operation as in Example 1 except that the amount of polyol (polyol for viscoelastic polyurethane A-013 (non-catalyst added product): manufactured by Mitsui Chemicals, Inc.) was changed to 100 parts by mass without using a filler. The measurement results are shown in Table 2.

Comparative Example 2
The amount of filler (microballoon made of a copolymer mainly composed of polyvinylidene chloride, particle size 40-60 μm, density 0.043: manufactured by Matsumoto Yushi Co., Ltd.) was changed to 0.5 parts by mass, and polyol ( Viscoelastic polyurethane polyol A-013 (catalyst-free product): Mitsui Chemicals Co., Ltd.) was used in the same manner as in Example 1 except that the amount used was 99.5 parts by mass. The results are shown in Table 2.

Comparative Example 3
A 0.3 MPa diaphragm pump was used instead of the microballoon (particle size: 40 to 60 μm, density: 0.043, manufactured by Matsumoto Yushi Co., Ltd.) made of a copolymer mainly composed of polyvinylidene chloride having a density of 0.028. Immediately after the pipeline was circulated by the dispenser, the same operation and measurement as in Example 1 were performed except that a dispenser and a fixed amount of isocyanate stored in a separate tank were discharged and cast into a mold. Indicated.

Comparative Example 4
A 0.3 MPa diaphragm pump was used instead of the microballoon (particle size: 40 to 60 μm, density: 0.043, manufactured by Matsumoto Yushi Co., Ltd.) made of a copolymer mainly composed of polyvinylidene chloride having a density of 0.028. After carrying out the pipeline circulation according to 72 hours, the same operation and measurement as in Example 1 were performed except that a dispenser was used to dispense a fixed amount of isocyanate stored in a separate tank and cast into a mold. Are shown in Table 2.

Comparative Example 5
The same operations and measurements as in Example 1 were performed except that the dehydrating agent (Molecular Sieve 3A: manufactured by Union Showa Co., Ltd.) was not used, and the measurement results are shown in Table 2.

Comparative Example 6
The same operation and measurement as in Example 1 were performed except that the amount of the dehydrating agent (Molecular Sieve 3A: manufactured by Union Showa Co., Ltd.) was changed to 0.25 part by mass, and each measurement result is shown in Table 2.

Reference example 1: Molding processing example using lead catalyst Microballoon (particle size: 40-60 μm) made of Matsumoto Yushi Co., Ltd. made of a copolymer mainly composed of polyvinylidene chloride, which is a filler as a lightening agent. , Density 0.043) Polyol containing 2 parts by mass (polyol for viscoelastic polyurethane A-013 (catalyst-free product): manufactured by Mitsui Chemicals, Inc.) 100 parts by mass (the amount used as a polyol is 98 parts by mass) Was stirred in order to re-disperse the balloon that was floating and separated during storage, and 0.35 parts by mass of lead octylate (BTP24: manufactured by Activator Chemical Co., Ltd.) as a catalyst and 0. 25 parts by mass was added and stirred. The moisture content of the mixture is shown in Table 2.
The mixture then circulated through the pipeline to prevent re-aggregation, and dispensed with 17.0 parts by weight of isocyanate (carbodiimide-modified MDI Cosmonate LK: manufactured by Mitsui Chemicals) stored in a separate tank. Then, the mixture was poured into a mold and heated to 70 ° C. to accelerate the curing, and the mold release possible time, final hardness arrival time, final hardness, presence / absence of blocking, density and tan δ were measured.
The measurement results are shown in Table 2.

Results From Examples 1 to 6, A) A polyol component having a moisture content of 550 ppm or less was prepared by adding a filler having a density of 0.035 to 0.050, a curing catalyst, a cocatalyst and a dehydrating agent to the polyol. The blending amount of the filler is 1.0% by mass or more based on the total mass of the polyol and the filler, and B) a mixing step of mixing the polyol component with the isocyanate component under uniform mixing conditions. And a curing step of casting the mixture obtained in C) B) into a mold, heat-curing, and producing the ultra-soft polyurethane, by the method for producing an ultra-soft polyurethane of the present invention, It was clearly shown that an ultra-soft polyurethane having a cast cured product with a Shore 00 hardness of 20 to 80, a density of 0.65 to 0.85 and a tan δ of 0.3 or more can be obtained.
Examples 2 and 3 are examples in which the final hardness (Shore 00) was increased by increasing the amount of isocyanate component added (NCO / OH equivalent ratio).
A graph showing the correlation between Shore 00 hardness and tan δ is shown in FIG.
As can be seen from FIG. 1, when the Shore 00 hardness is 80 or less, tan δ is 0.3 or more.
Example 4 is an example in which the amount of dehydrating agent (molecular sieve 3A) added was increased to reduce the moisture content in the system.
In Examples 5 and 6, the addition amount of the dehydrating agent (molecular sieve 3A) was increased, and the addition amount of the microballoon as a filler was changed. In Example 5, the addition amount was reduced to reduce the amount of cast cured product. In Example 6, the density was increased, and the amount added was increased to decrease the density of the cast cured product.

On the other hand, in Comparative Example 1 in which the microballoon as a filler was not used, blocking occurred, and the density of the cast cured product was 1.09, exceeding 0.65 to 0.85.
Further, in Comparative Example 2 in which the addition amount of the microballoon is less than 1.0% by mass based on the total mass of the polyol and the filler, the density of the cast cured product is generated while blocking occurs. Was 0.93, exceeding 0.65 to 0.85.
In addition, as a filler, a microballoon having a density of 0.028 smaller than 0.035 to 0.050 is used, and pumping is performed using a 0.3 MPa diaphragm pump with less impact. Immediately after pipeline circulation, In Comparative Example 3 in which a dispenser dispensed with isocyanate stored in a separate tank and poured into a mold, the destruction of the microballoon was avoided, so the density was 0.62 and an increase in density was avoided, The mechanical strength of the obtained cast cured product was low.
In Comparative Example 4 which is different from Comparative Example 3 only in that the pipeline circulation was performed for 72 hours, the microballoon was broken despite the use of a 0.3 MPa diaphragm pump having a small impact, and as a result, cast hardening was performed. The product density was 1.03, exceeding the density range of 0.65 to 0.85.
In addition, the graph which shows the correlation of the density of a microballoon and its destruction rate (after 72 hours of pipeline circulation using a 0.3 MPa diaphragm pump) was shown as FIG.
As can be seen from the graph, when the density of the microballoon is smaller than 0.035, the destruction rate exceeds 60%.
Further, in Comparative Example 5 in which no dehydrating agent (molecular sieve 3A) was used, the water content of the mixture became 1000 ppm exceeding 550 ppm, and the activity of the catalyst (bismuth octylate) was deactivated by water, and as a result, obtained. The demolding time of the cast cured product was 20 minutes exceeding 10 minutes, and the final hardness reaching time was 120 minutes exceeding 60 minutes.
Further, even in Comparative Example 6 where the amount of the dehydrating agent (molecular sieve 3A) is small and the moisture content of the mixture exceeds 700 ppm and becomes 700 ppm, the demolding time of the cast cured product is 13 minutes exceeding 10 minutes. The hardness reaching time was 60 minutes.
In addition, the graph which shows the correlation of the moisture content (ppm) of a polyol component and the demolding possible time (minutes) of a cast hardening product was shown as FIG.
As can be seen from the graph, when the moisture content (ppm) of the polyol component exceeds 550 ppm, the demoldable time (minutes) of the cast cured product exceeds 10 minutes.

Reference Example 1 is an example of molding using a lead catalyst that has been widely used in the past, but does not use a dehydrating agent (molecular sieve 3A), so that the moisture content of the polyol component is 800 ppm, which exceeds 550 ppm. The catalytic activity was not deactivated by water, and therefore, the demolding time of the cast cured product obtained was 7 minutes, which was within 10 minutes, and the final hardness arrival time was 30 minutes, which was within 60 minutes.
However, since the lead catalyst has an environmental problem as described above, the cast cured product produced in Reference Example 1 containing the catalyst has a problem in its use.

  According to the present invention, it can be used in a wide range of fields such as health, sports, medical care, protection of precision parts, transportation, etc., and there is no problem with physical properties in normal usage, and the specific gravity that people feel light (0.65 to 0.85) It is possible to provide an ultra-soft polyurethane molded article having excellent energy absorption performance with a tan δ of 0.3 or more without causing blocking that becomes a problem during storage and secondary processing.

Claims (7)

A method for producing an ultra-soft polyurethane having a Shore 00 hardness of 20 to 80, a density of 0.65 to 0.85, and a tan δ of 0.3 or more of a molded product after heat curing,
A) A polyol component having a moisture content of 550 ppm or less is prepared by adding a filler having a density of 0.035 to 0.050 to the polyol, a curing catalyst, a co-catalyst and a dehydrating agent. In this case, the blending amount of the filler is A preparation step of 1.0% by weight or more based on the total weight of polyol and filler;
B) a mixing step of mixing the polyol component with an isocyanate component under uniform mixing conditions;
C) A production method including a curing step of casting the mixture obtained in B) into a mold and heat-curing to produce the ultra-soft polyurethane. 2. The production method according to claim 1, wherein the filler is an organic microballoon having a particle diameter of 40 to 60 [mu] m and made of a polyvinylidene chloride-based copolymer. The method according to claim 1 or 2, wherein the curing catalyst is bismuth octylate. The production method according to any one of claims 1 to 3, wherein the dehydrating agent is a synthetic zeolite. The manufacturing method according to any one of claims 1 to 4, wherein in the preparation step, the moisture content of the polyol component is set to 300 ppm or less by adding a dehydrating agent. The production method according to any one of claims 1 to 5, wherein the uniform mixing of the polyol component is performed by pipeline circulation in which the polyol component is circulated in an endless pipeline. 7. A cast cured product having a pot life of 2 minutes or more in the curing step, which can be demolded within 10 minutes and reaches the final hardness within 60 minutes, is obtained. The manufacturing method of any one of these.

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