JP2008274051A - Polyisocyanate composition for flexible polyurethane foam and method for producing flexible polyurethane foam using the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible polyurethane foam having good storage stability and good impact resilience and mechanical properties. <P>SOLUTION: The polyisocyanate composition for flexible polyurethane foam is produced by urethanizing pure MDI (i) with not more than an equivalent of a polyol (ii) under the following conditions and mixing the product with a polymeric MDI (iii). The ratio of (2,2'-MDI+2,4'-MDI)/MDI is 60-85 mass%; the ratio of MDI/((i)+(iii)) is 50-90 mass%, and the compound (ii) is a polyether polyol having a number-average molecular weight of 700-10,000, an average functional group number of 2-8 and an oxyethylene content of 10-40% in the repeating unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyisocyanate composition for flexible polyurethane foam and a method for producing a flexible polyurethane foam using the composition. More specifically, the present invention relates to a polyisocyanate composition capable of obtaining a flexible polyurethane foam having excellent mechanical properties, impact resilience, and compression set, and a method for producing a flexible polyurethane foam characterized by using the composition.

  Flexible polyurethane foam is cut to an appropriate size or molded with a product-shaped mold, etc., and cushioning materials for furniture and automobile seats, mattresses for bedding, pillows, industrial sealing materials, soundproofing materials, etc. Used for applications. In recent years, with the aging of the population, there is an increasing need for good support for furniture and mattress applications, as well as a highly flame retardant foam. In production sites, high-reactivity, high-physical properties and high-curing raw material systems with high production efficiency are desired.

In general, flexible polyurethane foams use tolylene diisocyanate (hereinafter abbreviated as TDI) as the main isocyanate component, but an alternative isocyanate is desired at the production site due to odor and toxicity.
Diphenylmethane diisocyanate (hereinafter abbreviated as MDI) is well known as an alternative isocyanate, but it is said to have poor mechanical properties and rebound resilience compared to TDI-based isocyanate. While it is widely known that MDI isocyanate is used to improve the impact resilience by increasing the number of functional groups and average molecular weight of the polyol, which is the main component of the polyol premix, the disadvantage of mechanical properties deteriorates. It was difficult to form a high-performance urethane foam only by changing the premix components.

  In producing a flexible foam, various proposals have been made in order to obtain excellent physical properties. For example, in Patent Document 1, diphenylmethane diisocyanate (hereinafter abbreviated as pure MDI) containing 25 to 70% by weight of 2,4′-diphenylmethane diisocyanate (hereinafter abbreviated as 2,4′-MDI) and 50 to 90% by weight of A polyisocyanate composition comprising a reaction product having an NCO content of 2 to 31% by weight of a polyether polyol having an oxyethylene content, a number average hydroxyl equivalent weight of 700 to 2000 and an average nominal functional group number of 2 to 6; Disclosed is a process for producing foams using isocyanates.

  Patent Document 2 discloses that diphenylmethane diisocyanate containing 5 to 30% by mass of 2,4′-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate containing diphenylmethane diisocyanate, oxyethylene content of less than 50% by mass and the number of functional groups. Is obtained by reacting a polyether polyol having an average hydroxyl equivalent weight of 200 to 2500 with an oxyethylene content of 50% by mass or more and an average hydroxyl equivalent weight of 200 to 2500 A method for producing a flexible polyurethane foam using a polyisocyanate composition having an isocyanate group content of 10 to 25% by mass is disclosed.

However, all the conventional methods for producing flexible polyurethane foam, including the methods described in Patent Documents 1 and 2, are storage stability of the polyisocyanate composition to be used, moldability such as releasability at the time of reactive foaming, and curing properties. And at least one of mechanical properties and rebound resilience of the resulting flexible polyurethane foam has not been sufficient. Further, although Patent Document 1 describes diphenylmethane diisocyanate containing 25 to 70% by weight of 2,4′-MDI, only 30% by weight is described in the examples, and mechanical properties, etc. The effect is not disclosed.

JP 9-041265 A JP 2001-2749 A

The present invention has been made in view of the above-described problems of the prior art, and the following (i) to (iii)
An object of the present invention is to provide a polyisocyanate composition capable of achieving a high level in a balanced manner with respect to all of the above points and a method for producing a flexible polyurethane foam using the same.
(i) The storage stability of the polyisocyanate composition is high.
(ii) Good moldability such as releasability and curing at the time of reactive foaming.
(iii) A flexible polyurethane foam excellent in mechanical properties such as tear strength and tensile strength, wet heat compression set and impact resilience is obtained.

I. In the polyisocyanate composition for flexible polyurethane foam obtained by subjecting pure MDI (I) to a urethanization reaction with a polyol (B) having an equivalent weight or less and then mixing polymeric MDI (C),
In the total amount of diphenylmethane diisocyanate components derived from (i) and (c), the total content of 2,2′-diphenylmethane diisocyanate and 2,4′-diphenylmethane diisocyanate is 60 to 85% by mass,
The content of the diphenylmethane diisocyanate component derived from (A) and (C) with respect to the total amount of (A) and (C) is 50 to 85% by mass,
(B) is a polyether polyol having a number average molecular weight of 700 to 10,000, an average number of functional groups of 2 to 8, and an oxyethylene group in the repeating unit of 10 to 40%. Composition.
II. In the polyisocyanate composition for flexible polyurethane foam obtained by subjecting polymeric MDI (c ′) to a urethanization reaction with a polyol (b) having an equivalent amount or less,
In the diphenylmethane diisocyanate component derived from (ha ′), the total content of 2,2′-diphenylmethane diisocyanate and 2,4′-diphenylmethane diisocyanate is 60 to 85% by mass,
The content of the diphenylmethane diisocyanate component in (ha ′) is 50 to 85% by mass,
(B) is a polyether polyol having a number average molecular weight of 700 to 10,000, an average number of functional groups of 2 to 8, and an oxyethylene group in the repeating unit of 10 to 40%. Composition.
III. In the method for producing a flexible polyurethane foam obtained by reaction foaming of a mixed liquid of polyisocyanate (A), polyol (B), foaming agent (C), catalyst (D), and foam stabilizer (E),
A method for producing a flexible polyurethane foam, wherein the polyisocyanate (A) uses the polyisocyanate composition according to claim 1 or 2.
IV. Production of a flexible polyurethane mold foam obtained by injecting a mixed liquid of polyisocyanate (A), polyol (B), foaming agent (C), catalyst (D) and foam stabilizer (E) into a mold and reactive foaming In the method
A method for producing a flexible polyurethane mold foam, wherein the polyisocyanate (A) uses the polyisocyanate composition according to claim 1 or 2.

  According to the present invention, it is possible to provide a flexible polyurethane foam having a tear strength of 6 N / cm or more, a wet heat compression set of 30% or less, and a rebound elastic modulus of 50% or more. Also, the polyisocyanate composition used to obtain this flexible polyurethane foam exhibits good storage stability.

  First, raw materials used in the polyisocyanate composition for flexible polyurethane foam of the present invention will be described.

Pure MDI (I) used in the present invention is
General chemical formula: OCN-C6H4-CH2-C6H4-NCO
And having two benzene rings and two isocyanate groups in one molecule, which is called a binuclear body. (Ii) includes 2,2'-diphenylmethane diisocyanate (hereinafter abbreviated as 2,2'-MDI), 2,4'-MDI, 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as 4,4'-MDI). There are three types of isomers.

  The polyol (b) used in the present invention is a polyether polyol having a number average molecular weight of 700 to 10,000, an average number of functional groups of 2 to 8, and an oxyethylene group in the repeating unit of 10 to 40%.

  Polymeric MDI (c) used in the present invention (c) is obtained by converting an amino group to an isocyanate group by phosgenation or the like of a condensation mixture (polyamine) obtained by a condensation reaction of aniline and formalin. It means a mixture of organic isocyanate compounds having different degrees of condensation, and the composition of the finally obtained polymeric MDI can be changed by changing the raw material composition ratio and reaction conditions during condensation and by separation by distillation or crystallization. Since polymeric MDI is obtained in this way, it contains a pure MDI component called a so-called dinuclear body. The polymeric MDI (c) and (c ') used in the present invention are partly distilled from a pure MDI component, further added with pure MDI, and have different reaction conditions and separation conditions. It may be a mixture of several polymeric MDIs such as those.

  The polyisocyanate composition for flexible polyurethane foam according to the present invention is obtained by urethanizing the above-mentioned pure MDI (I) with an equivalent or less polyol (B) and then mixing with polymeric MDI (C), or It is obtained by subjecting polymeric MDI (c ′) to a urethanization reaction with a polyol (b) having an equivalent weight or less. The isocyanate content of the polyisocyanate composition for flexible polyurethane foam thus obtained is 20 to 33% by mass, preferably 23 to 31% by mass.

  In the present invention, the total amount of diphenylmethane diisocyanate components derived from (i) and (ha) or (ha ′) (total dinuclear body), 2,2′-MDI and 2,4′-MDI are 60 to It is essential that the content of the MDI component is 50 to 90% by mass, and the total amount of (I) and (C) or (C ') (total amount of isocyanate raw materials) is 85 to 90% by mass, A total of 60 to 80% by mass of 2,2′-MDI and 2,4′-MDI in all dinuclear bodies is contained, and the content of the MDI component is 60 to 80% by mass with respect to the total amount of isocyanate raw materials.

  When the total content of 2,2'-MDI and 2,4'-MDI in the dinuclear body is less than 60 or more than 85% by mass, the storage stability of the polyisocyanate composition is deteriorated. Furthermore, if it exceeds 85% by mass, the expansion ratio is lowered, and the flexible polyurethane foam cannot be satisfactorily filled in the mold. Further, when the MDI content with respect to the total amount of isocyanate raw material is less than 50% by mass, the tear strength and elongation at break are small, and when it exceeds 90% by mass, the compression set is large.

4,4′-MDI is an isomer constituting MDI according to the present invention together with 2,4′-MDI.
The content of -MDI and 2,2'-MDI is not particularly limited, but the content of 4,4'-MDI is about 13 to 39.9 mass%, and the content of 2,2'-MDI is 0.1 to 2 mass % Is preferable.

  In the polyol (b) used for the synthesis of the polyisocyanate composition of the present invention, the oxyethylene group content needs to be 1 to 40% by mass, and more preferably 10 to 20% by mass. . When the oxyethylene content is less than 1% by mass, compression set in a wet state (Wet) is deteriorated. On the other hand, when the content exceeds 40% by mass, the resulting polyisocyanate composition has a molding stability such as depression. In addition to worsening, the mechanical strength of the foam is reduced.

  Moreover, in the polyol (b) according to the present invention, it is necessary that the average hydroxyl equivalent is 700 to 10,000 (more preferably 1000 to 5000) and the nominal average functional group number is 2 to 6, and the number average molecular weight is 1400. It is preferably ˜12000. When the average hydroxyl equivalent is less than 700, the flexibility of the obtained polyurethane foam is lowered, and when it exceeds 10,000, the mechanical strength of the obtained polyurethane foam is lowered. The “nominal average functional group number” refers to the (average) functional group number of the initiator used for obtaining the polyol.

  The reaction temperature for synthesizing the MDI prepolymer is 15 to 150 ° C, preferably 40 to 100 ° C, and a urethanization catalyst described later may be added during the reaction.

  Examples of the urethanization catalyst include organic metal compounds such as dibutyltin dilaurate and dioctyltin dilaurate, organic amines such as triethylenediamine and triethylamine, and salts thereof.

  The isocyanate composition for the flexible polyurethane foam thus obtained has good storage stability, and the flexible polyurethane foam obtained by using this isocyanate composition is also excellent while having high opportunity physical properties. A flexible polyurethane foam having high impact resilience and compression set can be provided. The isocyanate composition for flexible polyurethane foam of the present invention is particularly suitable for mold foaming formulations.

  Next, a method for producing the flexible polyurethane foam of the present invention will be described.

  In the method for producing a flexible polyurethane foam in which a polyisocyanate (A) and a polyol (B) are reacted in the presence of a foaming agent (C), a catalyst (D), and a foam stabilizer (E), the polyisocyanate (A) It is characterized by using the above-mentioned polyisocyanate composition.

  As the polyol (B), any of those used in the urethane industry can be used. For example, polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols and other polymer polyols having a number average molecular weight of 1,000 or more, castor oil, Examples include polyols derived from natural fats and oils typified by soybean oil, palm oil, low molecular polyols having a molecular weight of less than 1,000, low molecular polyamines, and low molecular amino alcohols. In the present invention, it is preferable that the polyol (B) is mainly composed of a polyether polyol having a number average molecular weight of 1,000 to 10,000 and a nominal functional group of 2 to 6 that easily exhibits physical properties as a flexible polyurethane foam. . The “nominal functional group number” corresponds to the number of active hydrogens in the initiator (not the number of active hydrogen groups).

As this polyether polyol, known ones can be used, and (number average) low molecular polyols having a molecular weight of less than 1,000, low molecular polyamines, low molecular amino alcohols, etc. are used as initiators for ethylene oxide and propylene oxide. And the like obtained by adding cyclic ethers such as alkylene oxide and tetrahydrofuran. As the initiator, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, 2, 2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3 -Hexanediol, 2-n-hexadecane-1,2-ethylene glycol, 2-n-eicosane-1,2-ethylene glycol, 2-n-octaco 1,2-ethylene glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, or ethylene oxide or propylene oxide adduct of bisphenol A, hydrogenated bisphenol A, 3-hydroxy-2,2-dimethylpropyl Low molecular polyols such as -3-hydroxy-2,2-dimethylpropionate, trimethylolpropane, glycerin, pentaerythritol, aniline, ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc. Low molecular amines such as monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine and other low molecular amino alcohols It is below.
For the purpose of adjusting the hardness, a polymer polyol produced by polymerizing a vinyl monomer in a polyol by an ordinary method is used. A polyether polyol similar to that described above is used, and a vinyl polymer is polymerized and stably dispersed in the presence of a radical initiator. Examples of the vinyl polymer include acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl, methacrylate, and alkyl methacrylate. Of these, acrylonitrile and styrene are preferable. Specific examples of the polymer polyol include EL-910 and EL-923 manufactured by Asahi Glass Urethane Co., Ltd. and FA-728R manufactured by Sanyo Chemical Industries.

  As the foaming agent (C), carbon dioxide gas generated by the reaction of an isocyanate group and water can be used. In addition, a small amount of a low-boiling organic compound such as cyclopentane, normal pentane, isopentane, or HFC-245fa is used. It can be used together or formed by mixing and dissolving air, nitrogen gas, liquefied carbon dioxide, etc. in the stock solution using a gas loading device. The preferred blowing agent of the present invention is water. Although the preferable addition amount of a foaming agent (D) is based on the setting density of the product obtained, it is 0.5-15 mass% normally with respect to a polyol (B).

  As the catalyst (D), various urethanization catalysts known in the art can be used. For example, triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N, N, N ′, N′-tetramethylhexamethylenediamine, N, N, N ′, N ′ , N ″ -pentamethyldiethylenetriamine, bis- (2-dimethylaminoethyl) ether, triethylenediamine, 1,8-diaza-bicyclo (5,4,0) undecene-7, 1,2-dimethylimidazole, 1-butyl Tertiary amines such as 2-methylimidazole, reactive amines such as dimethylethanolamine, N-trioxyethylene-N, N-dimethylamine, N, N-dimethyl-N-hexanolamine, or organic acids thereof Salt, stannous octoate, dibutyltin dilaurate, zinc naphthenate The preferred amount of mentioned organometallic compounds such as are. Catalyst (C), the polyol (B), from 0.01 to 10 wt%.

  As the foam stabilizer (E), organosilicon surfactants known in the art can be used. For example, L-520, L-540, L-5309, L-5366, SZ- from Nippon Unicar 1306, SRX-274C, SF-2962, SF-2964 made by Toray Dow Corning, DC-5169, DC-193 made by Air Products, F-122, F-220, F-341 made by Shin-Etsu Chemical, etc. Can be mentioned. The preferable addition amount of a foam stabilizer (E) is 0.1-10 mass% with respect to a polyol (B).

  Furthermore, flame retardants, plasticizers, antioxidants, ultraviolet absorbers, colorants, various fillers, internal mold release agents, and other processing aids can be added and used as necessary. Of these auxiliaries, those that do not have an active hydrogen group capable of reacting with isocyanate can be mixed with polyisocyanate in advance and used. In addition to the polyisocyanate (A), the polyol (B), the foaming agent (C), the catalyst (D), the foam stabilizer (E), and if necessary, a crosslinking agent and additives are mixed in advance to form a polyol premix.

  A method for producing a flexible polyurethane mold foam according to the present invention comprises injecting the soft polyurethane foam stock solution of the above (A) to (E) into a mold, followed by foaming and curing. Can be used.

  The mold temperature when the foaming stock solution is poured into the mold is usually 30 ° C. or higher, preferably 40 ° C. or higher, and the upper limit is usually 70 ° C. or lower, preferably 60 ° C. or lower. If the mold temperature when the foaming stock solution is poured into the mold is less than 30 ° C., the curing property is lowered, whereas if it is higher than 70 ° C., the foam surface is roughened, and the cost is increased due to an increase in energy cost. Can be a disadvantage.

  The time for curing the foaming stock solution in the mold is usually 3 minutes or longer, preferably 4 minutes or longer, and the upper limit is usually 8 minutes or shorter, preferably 6 minutes or shorter. If the curing time for foaming and curing the above-mentioned foaming stock solution is shorter than 3 minutes, the curing property may be lowered. On the other hand, if it is longer than 8 minutes, the energy cost is increased and the obtained foam may shrink. is there.

  When producing the flexible polyurethane mold foam of the present invention, it is preferable to mix the polyisocyanate component and the polyol component immediately before foaming using a high pressure foaming machine, a low pressure foaming machine or the like. It is preferable that the isocyanate index (isocyanate group / active hydrogen group × 100) indicating the mixing ratio of the polyisocyanate component and the polyol premix component is 60 to 150, preferably 70 to 110. When the isocyanate index is less than 60, the resilience and mechanical properties of the foam obtained are remarkably deteriorated, and when the isocyanate index is 150 or more, the curing property and molding stability are deteriorated.

  The liquid mixture obtained by the foaming machine is discharged into a mold (mold), foamed and cured, and then demolded. In order to perform the demolding smoothly, it is also preferable to apply a release agent to the mold in advance. The release agent to be used may be a release agent usually used in the field of molding processing, and is not particularly limited. However, from the viewpoint of suppressing unnecessary foaming of the foaming stock solution, the wax solvent is used in the present invention. It is preferable to use a system release agent. In addition, the product after demolding can be used as it is, but in order to prevent foam shrinkage, the cell is destroyed by compression or decompression by a conventionally known method to stabilize the appearance and dimensions of the product. You can also.

Furthermore, the manufacturing method of a slab foam can be used as a manufacturing method of the flexible polyurethane foam using the polyisocyanate composition of this invention. The slab foam is produced by mixing the isocyanate and polyol premix using a low-pressure foaming machine or high-pressure foaming machine, and continuously supplying the mixture on a belt conveyor for foaming, or in a batch-type mixing tank. There is a method called batch block in which foaming is performed by pouring.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these. In the examples and comparative examples, “%” indicates “mass%” and “ratio (ratio)” indicates “mass ratio (ratio)” unless otherwise specified.

[Synthesis of Polyisocyanate (A)]
(Synthesis Example 1)
A reactor equipped with a stirrer, a cooling tube, a nitrogen introduction tube, and a thermometer was charged with 16 kg of MDI-1, 46 kg of MDI-2, and 23 kg of polyol-1 and reacted at 80 ° C. for 5 hours while stirring. Next, 15 kg of PMDI-1 was charged and stirred at 40 ° C. for 30 minutes to obtain polyisocyanate NCO-1. The NCO content of NCO-1 was 25%. When NCO-1 was stored in a dark place at 0 ° C., no precipitation occurred even after 90 days.

(Synthesis Examples 2 to 6)
Using the same production apparatus as in Synthesis Example 1, pure MDI and polyol were reacted according to the composition shown in Table 1, and then polymeric MDI was mixed to produce NCO-2 to 6. The reaction temperature and time are the same as in Synthesis Example 1. Table 1 shows the properties of the resulting polyisocyanate composition. In addition, the storage stability in a 0 degreeC dark room is the elapsed days when precipitation etc. were recognized for the first time when the obtained polyisocyanate composition was preserve | saved in the dark place of 0 degreeC.

(Synthesis Examples 7-9)
Using the same production apparatus as in Synthesis Example 1, instead of using polyol 1, polyol 2 was used and reacted with pure MDI and polyol according to the mixing ratio in Table 2, and then mixed with polymeric MDI. NCO-7-9 were produced. The reaction temperature and time are the same as in Synthesis Example 1. Properties of the obtained polyisocyanate composition are shown in Table 2.

(Synthesis Examples 10-14)
In the same production apparatus as in Synthesis Example 1, pure MDI and polymeric MDI were mixed according to the blending ratio in Table 3, and then reacted with polyol to produce NCO-10-14. The reaction temperature and time are the same as in Synthesis Example 1. Table 3 shows the properties of the obtained polyisocyanate composition.

(Synthesis Examples 15 to 19)
In the same production apparatus as in Synthesis Example 1, pure MDI and polymeric MDI were mixed according to the blending ratio in Table 4, and then reacted with polyol to produce NCO-15-19. The reaction temperature and time are the same as in Synthesis Example 1. Properties of the obtained polyisocyanate composition are shown in Table 4.

The raw materials used in synthesizing NCO1 to NCO19 are described below.

MDI-1: Pure MDI
4,4′-MDI content = 100%
MDI-2: Pure MDI
2,4′-MDI content = 98%
PMDI-1: Polymeric MDI
Pure MDI content = 45%
4,4′-MDI content in MDI = 40%
PMDI-2: Polymeric MDI
Pure MDI content = 50%
4,4′-MDI content in MDI = 0%
Polyol-1: Polyoxyethylene polyoxypropylene polyol
Nominal average functional group number = 4
Number average molecular weight = 8000
Hydroxyl value = 28 mgKOH / g
Oxyethylene group content = 13%
Product name: EL-838, polyol-2 manufactured by Asahi Glass Co., Ltd .: polyoxyethylene polyoxypropylene polyol
Nominal average functional group number = 4
Number average molecular weight = 8000
Hydroxyl value = 28 mgKOH / g
Oxyethylene group content = 80%
Product name: QB-8000, Toho Chemical Industries polyol-3: Polyoxypropylene polyol
Nominal average functional group = 2
Number average molecular weight = 4000
Hydroxyl value = 28 mgKOH / g
Oxyethylene group content = 0%
Product name: PP-4000, Sanyo Chemical Industries polyol-4: Polyoxyethylene polyol
Nominal average functional group = 2
Number average molecular weight = 4000
Hydroxyl value = 28 mgKOH / g
Oxyethylene group content = 100%
Product name: PEG-4000, manufactured by Sanyo Chemical Industries

[Preparation of polyol premix]
In a reactor equipped with a stirrer, 3 kg of polyol 2, 95 kg of polyol-5, 5 kg of polyol-6, 5.2 kg of blowing agent-1, 0.2 kg of catalyst-1, 0.55 kg of catalyst-2, 3 kg of catalyst-3 and 1 kg of foam stabilizer-1 were charged and mixed uniformly.

In the above polyol premix

Polyol-5: Polyoxyethylene polyoxypropylene polyol
Nominal average functional group = 3
Number average molecular weight = 6000
Hydroxyl value = 28 mgKOH / g
Oxyethylene group content = 17%
Product name: EL-837, Asahi Glass Co., Ltd. polyol-6: Polymer polyol
Hydroxyl value = 28 mgKOH / g
Product name: EL-910, Asahi Glass Co., Ltd. blowing agent-1: water catalyst-1: amine catalyst (Toyocat ET, manufactured by Tosoh Corporation)
Catalyst-2: Amine-based catalyst (Tosoh, TEDA L33)
Catalyst-3: Amine-based catalyst (Mitsui Chemicals, triethylamine)
Foam stabilizer-1: Silicone foam stabilizer (F-122 manufactured by Shin-Etsu Chemical Co., Ltd.)

  From the results in Tables 1 to 4, the polyisocyanate having a content of 2,2′-MDI and 2,4′-MDI of 60 to 85% by mass in the total amount of diphenylmethane diisocyanate component has good storage stability. 2,2′-MDI and 2,4′-MDI having a content of 60% by mass show that the storage stability is remarkably good.

[Manufacture of flexible polyurethane mold foam, evaluation of flexible polyurethane mold foam]
Example 1
NCO-1 and the aforementioned polyol premix were manufactured in accordance with the isocyanate indexes shown in Table 5, and a flexible polyurethane mold foam was produced in the following manner using a high pressure foaming machine manufactured by Cannon. The polyol premix adjusted to a raw material temperature of 23 ± 2 ° C. and an isocyanate component were mixed at a high pressure under a predetermined ratio and discharged to a mold (300 mm × 300 mm × 100 mmt) adjusted to a temperature of 60 ± 2 ° C. After 5 minutes, the mold was removed from the mold and the foam was crushed. The obtained foam was allowed to stand for 16 hours or more at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. Then, it cut | judged to the magnitude | size required for each physical-property measurement, and measured the physical property. The results are shown in Table 5. The physical properties are measured according to JIS 6400 (1997).

Examples 2-11, Comparative Examples 1-9
With the combinations and isocyanate indexes shown in Tables 5 to 8, a flexible polyurethane mold foam was produced in the same procedure as in Example 11, and various foam physical properties were measured. The results are shown in Tables 5-8. In Comparative Example 2, the foam was unfilled with respect to the size of the mold having an insufficient expansion ratio, and a molded product could not be obtained.
In Comparative Examples 3 to 5, since the content of oxyethylene group in the polyol (b) is 40% by mass or more, the foam collapses during the production of the flexible polyurethane foam, and the physical properties can be measured. I couldn't get the right form.
In Comparative Examples 6 and 7, when the oxyethylene content is low (Comparative Example 6), significant deterioration was observed in a significant wet heat compression strain test, and when the oxyethylene content is high (Comparative Example 7), the foam collapsed. However, a molded product could not be obtained.
In Table 8, the composition is the same as in Table 5, and no difference in physical properties due to the difference in the production method of the isocyanate composition is recognized.

  From Tables 5 to 8, the flexible polyurethane foam of the present invention has an appropriate range for the dinuclear content of the starting isocyanate and the total content of 2,2'-MDI and 2,4'-MDI of the dinuclear. This shows that the mechanical properties are improved. The conditions that the tear strength is 6 N / cm or more, the moist heat / humid compression set is 30% or less, and the rebound resilience is 50% or more are the contents of 2,2′-MDI and 2,4′-MDI, and oxyethylene Optimum conditions are determined by the content ratio. Further, from the viewpoint of storage stability which is industrially useful, an optimum ratio of the contents of 2,2′-MDI and 2,4′-MDI is derived.

[Manufacture of flexible polyurethane slab foam, evaluation of flexible polyurethane slab foam]
Example 11
A flexible polyurethane slab foam was produced in the following manner using NCO-1 and the above-mentioned polyol premix according to each formulation described in Table 5 using a low pressure foaming machine manufactured by Polymer Engineering. Each component temperature-controlled at a raw material temperature of 25 ± 2 ° C. is stirred and mixed at a predetermined ratio at a rotational speed of 4,500 rpm, and continuously discharged onto a conveyor having a width of 750 mm, having a length of 2,000 mm and a height of 700 mm. Slab foam blocks were molded. After crushing and allowing to stand overnight, the foam was cut into 300 mm × 300 mm × 50 mm, and the physical properties thereof were measured. As a result, a soft slab foam excellent in impact resilience and mechanical properties could be obtained.

Claims (4)

In the polyisocyanate composition for flexible polyurethane foam obtained by subjecting pure MDI (I) to a urethanization reaction with a polyol (B) having an equivalent weight or less and then mixing polymeric MDI (C),
In the total amount of diphenylmethane diisocyanate components derived from (i) and (c), the total content of 2,2′-diphenylmethane diisocyanate and 2,4′-diphenylmethane diisocyanate is 60 to 85% by mass,
The content of the diphenylmethane diisocyanate component derived from (A) and (C) with respect to the total amount of (A) and (C) is 50 to 85% by mass,
(B) is a polyether polyol having a number average molecular weight of 700 to 10,000, an average number of functional groups of 2 to 8, and an oxyethylene group in the repeating unit of 10 to 40%. Composition. In the polyisocyanate composition for flexible polyurethane foam obtained by subjecting polymeric MDI (c ′) to a urethanization reaction with a polyol (b) having an equivalent amount or less,
In the diphenylmethane diisocyanate component derived from (ha ′), the total content of 2,2′-diphenylmethane diisocyanate and 2,4′-diphenylmethane diisocyanate is 60 to 85% by mass,
The content of the diphenylmethane diisocyanate component in (ha ′) is 50 to 85% by mass,
(B) is a polyether polyol having a number average molecular weight of 700 to 10,000, an average number of functional groups of 2 to 8, and an oxyethylene group in the repeating unit of 10 to 40%. Composition. In the method for producing a flexible polyurethane foam obtained by reaction foaming of a mixed liquid of polyisocyanate (A), polyol (B), foaming agent (C), catalyst (D), and foam stabilizer (E),
A method for producing a flexible polyurethane foam, wherein the polyisocyanate (A) uses the polyisocyanate composition according to claim 1 or 2. Production of a flexible polyurethane mold foam obtained by injecting a mixed liquid of polyisocyanate (A), polyol (B), foaming agent (C), catalyst (D) and foam stabilizer (E) into a mold and reactive foaming In the method
A method for producing a flexible polyurethane mold foam, wherein the polyisocyanate (A) uses the polyisocyanate composition according to claim 1 or 2.