WO2008012908A1

WO2008012908A1 - Process for production of polyurethane foam

Info

Publication number: WO2008012908A1
Application number: PCT/JP2006/314948
Authority: WO
Inventors: Suguru Yamada; Naoyuki Ohmori; Kohji Yoshida; Hitoshi Yaguchi
Original assignee: Nippon Polyurethane Industry Co., Ltd
Priority date: 2006-07-28
Filing date: 2006-07-28
Publication date: 2008-01-31
Also published as: CN101501095A

Abstract

[PROBLEMS] To provide a process for producing a polyurethane foam having a higher durability than a conventional one produced by mechanical froth method. [MEANS FOR SOLVING PROBLEMS] A process for producing a polyurethane foam comprising the steps of mixing (A) an organic polyisocyanate, (B) a polyol, (C) a catalyst and (D) a foam controlling agent in a dispersed state to give a polyurethane foam forming composition, mixing an inert gas with the composition in a dispersed state by a mechanical agitation, foaming the resulting mixture and then curing the foamed product, the polyurethane foam having a poly(oxytetramethylene)polyol content of 50 to 80% by mass, and the foam controlling agent (D) being a dimethylpolysiloxane-polyether block copolymer which has a silicon content of 5 to 20% by mass, has a polyether moiety having an alkyl group at its terminus, and has a number average molecular weight of 1,000 to 2,000.

Description

Specification

Method for producing polyurethane foam

Technical field

The present invention relates to a method for producing a polyurethane foam having excellent durability and the like by a mechano-calfloss method.

Background art

[0002] Polyurethane foams by the mecha-calfloss method are used in rolls for copying machines, cosmetic puffs, carpets, packing, sealing materials, vibration damping materials, vibration damping materials, and the like. Various manufacturing methods such as the methods described in Patent Document 1 and Patent Document 2 have been proposed as a method for manufacturing a polyurethane foam by the mecha-calfs method.

[0003] Patent Document 1: Japanese Patent Laid-Open No. 2001-89547

Patent Document 2: Japanese Patent Laid-Open No. 10-258437

[0004] The production method of Patent Document 1 uses a foam stabilizer! /, So there is little problem of bleeding in the polyurethane foam obtained. However, the cell state of the polyurethane foam cells is uneven in cell size, and the hardness varies depending on the part. The manufacturing method of Patent Document 2 uses an alcohol-modified silicone oil and is subjected to centrifugal molding, so that a foam with few pinholes can be obtained. However, due to centrifugal molding, the molded product is thin, and is not suitable for molding block-like or thick products.

[0005] Among the polyols used in polyurethane foam, poly (oxytetramethylene) polyol (hereinafter abbreviated as “PTMG”) is derived from poly (oxypropylene) polyol (hereinafter abbreviated as “PPG”). Polyurethane foams with excellent physical properties such as mechanical strength, durability and impact resilience tend to be obtained.

[0006] However, the technology for producing polyurethane foam by the mechano-calf loss method using PTMG as the main polyol has not been established so far.

Disclosure of the invention

The invention's effect

[0007] The present invention relates to a method for producing a polyurethane foam by the mecha-calfloss method. Compared with the conventional polyurethane foam by the mecha-calfloss method, a highly durable polyurethane foam can be obtained.

Problems to be solved by the invention

[0008] An object of the present invention is to provide a method for producing a polyurethane foam having higher durability than that obtained by the conventional mechanical calfloss method.

Means for solving the problem

[0009] The present invention has been found as a result of intensive studies to solve the above-described problems, that is, organic polyisocyanate (A), polyol (B), catalyst (C), and In the method for producing a polyurethane foam, the polyurethane foam-forming composition in which the foam stabilizer (D) is dispersed and mixed is further mixed and dispersed with an inert gas by mechanical stirring, followed by foam curing.

The content of PTMG component in the obtained polyurethane foam is 50 to 80% by mass,

Dimethylpolysiloxane polyether block copolymer having a polyether content of 5 to 20% by mass of the foam stabilizer (D), a terminal alkyl group, and a number average molecular weight of 1,000 to 2,000. A method for producing the polyurethane foam, which is a coalescence.

[0010] The present invention also relates to an isocyanate group-terminal prepolymer obtained by reacting an organic polyisocyanate (A) force diphenylmethane diisocyanate (I) and PTMG (mouth). ) Force The process for producing polyurethane foam as described above, which comprises 70 to 90% by mass of PTMG (mouth).

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention relates to a method for producing a polyurethane foam by mecha-calfloss method using PTMG as a main polyol. Here, the main polyol of the polyurethane foam is defined as PTMG having a “PTMG component content” of 50 to 80% by mass.

Here, as a measuring method of “content of PTMG component”, for example, polyurethane foam is subjected to Colisch decomposition to recover PTMG, and as shown by the following formula, polyurethane before decomposition is recovered. It can be determined by the ratio of PTMG recovery to foam

[Number 1]

PTMG recovery rate (<½) (1) Mass of PTMG recovered after decomposition

^{PTM Ca} recovery Winter ^{/ 0j} Mass of flexible polyurethane foam before decomposition ^{X 1 0 0}

The organic polyisocyanate (A) used in the present invention is diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”), polyphenylene-polymethylene polyisocyanate (hereinafter referred to as “MDI”). Abbreviated as “MDI polynuclear condensate”), tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, naphthalene diene Isocyanates, hydrogenated cardimethane methane diisocyanates, hydrogenated xylylene diisocyanates, etc., and some of the isocyanate groups of compounds having these isocyanate groups are urethane, biuret, allophanate, carbodiene. For imide, uretonimine, oxazolidone, amide, imide, isocyanurate, uretdione, etc. Denatured ones are mentioned. These can be used alone or in combination of two or more as required.

[0014] MDI and polymeric MDI will be described in more detail.

MDI consists of 4,4'-dimethanemethane diisocyanate (hereinafter abbreviated as 4,4'-MDI), 2,4'-dimethanemethane diisocyanate (hereinafter, 2,4 '). — Abbreviated as MDI), 2, 2 '— diphenylmethane diisocyanate (hereinafter abbreviated as 2, 2 ′ — MDI) It exists in the form of a single item).

[0015] The MDI-based polynuclear mixture exists in the form of a mixture of compounds having three or more benzene rings to which isocyanate groups are bonded in one molecule and having different degrees of condensation. Usually, it is not supplied in the form of an MDI-based multinuclear mixture alone, but is supplied in the form of a mixture with MDI (a mixture of MDI and an MDI-based multinuclear mixture is abbreviated as “polymeric MDI”).

[0016] In the first place, polymeric MDI is obtained by converting an amino group to an isocyanate group by phosgene, etc., from a condensed mixture (polyamine) obtained by the condensation reaction of aline and formalin. The product is an MDI polynuclear mixture with a different degree of condensation from MDI. The composition of MDI and polymeric MDI can be changed by changing the raw material composition ratio and reaction conditions during condensation, or by removing a portion of MDI by distillation. The MDI content of polymeric MDI and the isomer composition ratio of MDI can be determined from the calibration curve force based on the area percentage of each peak obtained by gel permeation chromatography or gas chromatography.

[0017] In the present invention, in consideration of the working environment at the time of foam production, the formability of the foam, the physical properties of the resulting polyurethane foam, etc., the 4,4'-MDI content is 50% by mass or more, 4, 4 'polymeric MDI to MDI content containing MDI which is 50-100 mass ^_0/0, and the mixing ratio and heating conditions etc. during these Isoshianeto group-terminated urethane Prevost Rimmer preferred instrument actual forming shape In consideration, isocyanate group-terminated urethane prepolymers are preferred.

[0018] In this isocyanate group-terminated urethane prepolymer, an organic diisocyanate (the above-mentioned MDI is particularly preferred) and a polymer polyol described below are reacted in an atmosphere having an excess of isocyanate groups. The reaction temperature is preferably 50 to: LOO ° C. The blending ratio of organic polyisocyanate (A) and polyol) is almost the same, and considering the viscosity of isocyanate-terminated prepolymers, the isocyanate content is preferably 5 to 35% by weight, especially 8 to 15% by weight. Is preferred. Further, the organic diisocyanate Z polymer polyol = 20Z80 to 50Z50 (mass ratio) is preferable as the blending ratio of the organic diisocyanate and the polymer polyol in the production of the isocyanate group-terminated polymer. In order to secure the PTMG content in the polyurethane foam, the high molecular polyol in the isocyanate group-terminated prepolymer is desirably PTMG.

[0019] The polyol (Β) used in the present invention comprises a polymer polyol and a chain extender. Here, the polymer polyol means a polyol having a number average molecular weight of 500 or more, and the chain extender means a polyol having a number average molecular weight of less than 500.

[0020] Examples of the polymer polyol include polyether polyol, polyester polyol, polycarbonate polyol, and hydrophobic polyol. Preferred polymer high-molecular weight ヽ Number average molecular weight is 1,000 to 10,000, and 1,500 to 5,000 power is particularly preferred. If the number average molecular weight is too high, the foam hardness will tend to be too low. If the number average molecular weight is too small, the elasticity of the foam tends to be impaired.

[0021] Examples of polyether polyols include propylene glycol and ethylene glycol. , Glycerin, trimethylolpropane, hexanetriol and the like as starting materials, and those obtained by addition polymerization of alkylene oxide and those obtained by ring-opening addition of a low molecular cyclic ether.

[0022] Polyester polyols include condensed polyester polyols obtained by condensation of dicarboxylic acids and diols, triols, etc., latatone polyester polyols obtained by ring-opening polymerization of latatones based on diols and triols, and polyether polyols. Polyols such as ester-modified polyol ester-modified with rataton are preferably used.

[0023] Examples of the polycarbonate polyol include those obtained by a transesterification reaction between a low molecular polyol such as butanediol or hexanediol and a low molecular carbonate such as propylene carbonate or jetyl carbonate. As the hydrophobic polyol, polyisoprene polyol, polybutadiene polyol, hydrogenated polybutadiene polyol and the like are used.

[0024] These polymer polyol components may be used alone or in combination of two or more.

Also good. The polymer polyol in the polyol (B) preferably contains 70 to 95% by mass of PTMG. Further, the polyol used in combination with PTMG is preferably terminal EO-treated PPG.

[0025] Examples of the chain extender include ethylene glycol, propylene glycol, 1,4 butane diol, trimethylol propane, tetramethylene ether glycol, polyethylene glycol and the like. These chain extenders may be used alone or in combination of two or more. In the present invention, 1,4 butanediol is preferred. This is because 1,4-butanediol has a primary hydroxyl group and therefore has good reactivity, is liquid at room temperature, has excellent workability, has an appropriate molecular weight, and has excellent mechanical strength. Is obtained.

[0026] Examples of the catalyst (C) used in the present invention include monoamines such as triethylamine and dimethylcyclohexylamine, and diamines such as tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexanediamine. , Pentamethyljetylenetriamine, Triamines such as pentamethyldipropylenetriamine and tetramethyldardine, cyclic diamine, dimethylbiperazine, methylethylbiperazine, methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole and other cyclic amines, dimethyl Alcoholamines such as aminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxyethylpiperazine, hydroxyethylmorpholine, bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl) aminopropyl pills Ether amines such as ethers, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutinoletin marker peptide, dibutinoletin tiocanoloxylate, Buchinore tin dimaleate may be used in combination Jiokuchinore tin mercaptide, Jiokuchinore tin Chiokanorebo Kishireto, phenyl mercury propionate, alone catalyst publicly known organometallic compounds such as Otaten salt, or two or more kinds.

[0027] The foam stabilizer (D) used in the present invention is a dimethylpolysiloxane polyetherpolyol block copolymer having a content of 5 to 20% by mass, an alkyl group at the end, and a number average. It has a feature of having a polyether part having a molecular weight of 1,000 to 2,000.

[0028] If the foam stabilizer (D) falls outside even one of the above requirements, the formation of fine cells becomes insufficient and a uniform foam cannot be obtained.

[0029] The content of silicon is measured by an ashing method, specifically, by the following procedure.

Method for measuring the Ca content

1. Weigh sample accurately into crucible.

2. Heat the crucible and burn the contents.

3. Weigh the residue (ash) remaining in the crucible.

4. Calculate the key content according to the following formula.

[Equation 2] Hazardous Association Right and (Ο / Λ-Mass of remaining ash 3 2 _v . „ _N- Key ^S Suri ^(%) 1 ⁾ Mass of sample weighed first ^X ~ ^ ^{X 1 0 Q}

[0030] Qualification of the terminal alkyl group is performed by NMR measurement. The NMR measurement in the present invention Is as follows.

Model: Norwegian Duty 500 (FT-NMR)

Measurement frequency: 500MHz

[0031] The number average molecular weight of the polyether part of the foam stabilizer (D) can be determined by GPC measurement of the foam stabilizer by Colisch decomposition.

[0032] The present invention can also use other conventionally known additives as required, for example, an antioxidant, an ultraviolet absorber, a flame retardant, a colorant, a conductive agent, an insulating agent, and a luminescent agent. And antibacterial agents and fragrances.

[0033] In order to produce the polyurethane foam of the present invention using these raw materials, the polyisocyanate component, polyol component, catalyst, and other additives stored or prepared in separate containers. Is added to one mixing head while mixing an inert gas, mixed so that it is homogeneous, and the mixed solution is flowed on a conveyor on which a formwork and a bottom paper are laid, and is heated and cured, or the mixed solution is For example, a method of casting in a predetermined mold or the like and curing by heating. The foam obtained by such a method is a polyurethane foam having uniform fine cells and appropriate hardness.

[0034] The isocyanate index (isocyanate group Z active hydrogen group X 100) at this time is preferably 50 to 150, more preferably 60 to 120. If the index is too low, the foam surface will tend to stick. Also, if the index is too high, it may not foam, or it may collapse and a flexible foam may not be obtained.

[0035] The polyurethane foam thus obtained becomes a foam having a uniform and fine cell with a density of 0.3 to 0.9 gZcm ³ .

[0036] The polyurethane foam obtained by the present invention includes various rolls such as toner conveying rolls, transfer rolls, charging rolls and developing rolls of electrophotographic apparatuses, bedding such as pillows and mattresses, cosmetic puffs, packings, sealing materials, and carpets. Used in the fields of backing, vibration control materials, seismic isolation materials, vibration isolation materials, sound insulation materials, etc. Example

[0037] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In the examples and comparative examples, unless otherwise noted, the ratio is quality. It is a quantity ratio, and “%” is “mass%”.

[0038] [Analysis of foam stabilizer]

Table 1 shows the results of the measurement of the number average molecule of the content, the terminal group, and the polyether part of the foam stabilizers 1 to 4.

[0039] [Table 1]

[0040] In Table 1

Key content:

It was measured by the ashing method described above.

Terminal:

Confirmed by NMR.

Number average molecular weight of the polyether part

The recovered material was measured by GPC-IR after decomposition with Kollisch.

Use foam stabilizer

F— 341: Shin-Etsu Chemical Co., Ltd. silicone-based foam stabilizer

X20—1749: Silicone foam stabilizer made by Shin-Etsu Chemical Co., Ltd.

F- 374: Shin-Etsu Chemical Co., Ltd. silicone-based foam stabilizer

B-8471: Gold Schmidt silicone foam stabilizer

SZ— 1136: Silicone foam stabilizer made by Nippon Car

[Synthesis of isocyanate group-terminated urethane prepolymers]

Synthesis example

Capacity equipped with a stirrer, cooling pipe, nitrogen introduction pipe, thermometer: 1 L reactor was charged with 376 g of MDI-1 and 624 g of PTG-2000 and reacted at 80 ° C for 4 hours with stirring. An isocyanate group-terminated urethane prepolymer NCO-1 was obtained. The isocyanate content of NCO-1 was 10.0%.

[0042] In the synthesis example MDI-1:

Diphenylmethane diisocyanate (MDI) PTG-2000 containing 1% MDI isomer mixture:

PTMG with nominal average functional group number = 2, number average molecular weight = 2,000

Made by Hodogaya Chemical Industry

* MDI isomer mixture:

Mixtures of isomers other than 4, 4 'MDI (2, 2' — MDI and 2, 4 ^ — MDI)

[Preparation of polyol premix]

Formulation Examples 1-8

Capacity: A polyol premix OH-1 was prepared by charging the 2 L reactor shown in Table 2.

[0044] [Table 2]

[0045] Formulation Examples 1 to 8, in Table 2

PTG-2000:

Made by Hodogaya Chemical Industry

GL-3000:

Nominal average functional groups = 3, number average molecular weight = 3,000, oxyethylene group content = 11% terminal oxyethylene capped poly (oxypropylene) polyol Sanyo Chemical Industries

1, 4-BD:

1, 4 Butanediol

DOTDL:

Dioctyltin dilaurate

[Manufacture of polyurethane foam]

Example 1

Liquid temperature: 40 ° C polyol premix OH-1 and liquid temperature: 40 ° C polyisocyanate NCO-1 were mixed in the proportions shown in Table 4 and stirred for 1 minute to dry air Pour the mixed solution with the mixture into a mold (10cm x 10cm x 10cm, open top), then leave the mold filled with the mixed solution in a hot air oven adjusted to 120 ° C for 30 minutes, The foamed polyurethane raw material was cured. Polyurethane foam was produced by removing the mold force from the cured polyurethane foam.

[0047] Examples 2-3 and Comparative Examples 1-5

A polyurethane foam was produced in the same procedure as in Example 1 with the formulation shown in Table 3.

[0048] [Table 3]

*,: Incomprehensible reason

* 2: Actual measurement

* 3: Ratio of the number of cells per unit area when Example 1 is 1.0

[0049] [Evaluation of polyurethane foam]

The evaluation items and measurement method of the foam are as follows.

PTMG recovery rate:

Polyurethane foam was decomposed by Kolisch decomposition to recover PTMG, and the ratio of recovered PTMG to polyurethane foam before decomposition was calculated. Density and hardness:

Determined according to JIS K 6401.

Average number ratio of senor:

The number of cells existing on three arbitrarily selected cut surfaces was measured, and expressed as a relative ratio when Example 1 was set to 1.

Average cell diameter:

Measure the diameter of cells existing on three arbitrarily selected cut planes, and use the average value as the cell diameter.

It was.

From Table 2, the polyurethane foam obtained by the present invention has uniform fine cells and has a low density. On the other hand, in the comparative example, the bubble formation was not successful and the density was increased, or the bubble itself was not sufficiently formed.

Claims

The scope of the claims

[1] A polyurethane foam-forming composition in which organic polyisocyanate (A), polyol (B), catalyst (C), and foam stabilizer (D) are dispersed and mixed, and inert gas is mechanically stirred. In the method for producing a polyurethane foam obtained by mixing and dispersing by foaming and then curing by foaming, the content of the poly (oxytetramethylene) polyol component in the obtained polyurethane foam is 50 to 80% by mass,

Dimethylpolysiloxane polyether block copolymer having a polyether content of 5 to 20% by mass of the foam stabilizer (D), a terminal alkyl group, and a number average molecular weight of 1,000 to 2,000. A method for producing the polyurethane foam, characterized in that it is a coalescence

[2] Organic polyisocyanate (A) force Diisocyanate diisocyanate (i) and poly (oxytramethylene) polyol (mouth) are obtained by reacting isocyanate-terminated prepolymers with polyol (B) 2. The method for producing a polyurethane foam according to claim 1, wherein the poly (oxytetramethylene) polyol (mouth) contains 70 to 90% by mass.