JPS63168424A - Production of polyurethane molding - Google Patents

Abstract

PURPOSE:To obtain the title molding excellent in cushioning property and durability and useful for cushions of furniture and automobiles, by reacting a specified polyisocyanate material with a polyol component in the presence of a catalyst. CONSTITUTION:A polyisocyanate material (A) which is either a polyisocyanate composition (a) comprising 50-90wt.% diphenylmethane diisocyanate, 1-46wt.% diphenylmethane diisocyanate oligomer and 4-40wt.% carbodiimide derivative thereof or a polyol-modified product (b) of component (a) obtained by reacting component (a) with a polyol having 0.002-0.1, per NCO group of component (a), OH group, a mol.wt. of 2,000-8,000, a functionality of 2-4, and an ethylene oxide content of below 50% based on the total alkylene oxide in the polyether is reacted with a polyol component (B) which is a polyether-polyol or a polyester-polyol in the presence of an amine or organotin catalyst and, optionally, a silicone foam stabilizer, a crosslinking agent and a blowing agent.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing nine types of polyurethane molded articles including flexible polyurethane foam using a specific polyisocyanate raw material. provides a method for producing a soft 7 ohm material having particularly excellent cushioning properties and durability by reacting a low temperature storage stable polyisocyanate raw material with a polyol component. These polyurethane molded bodies have a high modulus of 7 ohms, making them ideal for furniture and automobile cushions.

[Conventional technology]

Conventionally, when producing soft foam, tolylene diisocyanate alone or a mixture of tolylene diisocyanate and crude diphenylmethane diisocyanate has been used as a polyisocyanate raw material, but tolylene diisocyanate has a high vapor pressure and is difficult to work with. There is a problem that the boundaries of the burial mounds are getting worse.

Therefore, in recent years, attempts have been made to create soft foams using only diphenylmethane diisocyanate compositions, which have a much lower vapor pressure.

[Problem that the invention seeks to solve]

In order to obtain a polyurethane foam with good foam elongation and tear strength by reacting the diphenylmethane diisocyanate composition with the polyol component, it is necessary to increase the diphenylmethane diisocyanate content in the diphenylmethane diisocyanate composition. However, when this content is increased, the impact resilience, hysteresis loss, and permanent set, which are characteristics of a soft elastic body, deteriorate. In addition, the storage stability becomes very poor, and there are many problems such as crystallization of diphenylmethane diisocyanate, the formation of dimers accompanying it, and clogging of piping tanks in some cases.

That is, in order to obtain good foam tensile properties, it is necessary to make the core content J1k higher than SOX, but on the other hand, this K deteriorates the elastic properties and storage stability.

In order to improve the low-temperature stability, we mainly use the molecule i4o
Urethane-modified incyanate reacted with ~1roo of polyol is used, but although this improves storage stability, the polyol molecular cap is small, resulting in poor cushioning properties (resilience, hysteresis loss) and break-in properties (permanent set). ) is not improved at all.

Means for Solving the Problem C] The above problem is solved by using diphenylmethane di as a polyisocyanate raw material in a method for producing a polyurethane molded article by reacting a polyisocyanate and a polyol in the presence of a catalyst. Contains isocyanate, diphenylmethane diisocyanate oligomers, and their carbodiimide forms, with a diphenylmethane diisocyanate valence of J0 to 5'0 by weight, a carbodiimide content of μ to μO weight i%, and a diphenylmethane diisocyanate oligomer content. or (if) the polyisocyanate composition and a molecular weight of 2000 NF, 000. The number of functional groups is λ~Hiroshi, the number of hydroxyl groups is 0.00λ~0.1ilI2 for one incyanato group, and the polyol with less than SOX is added to the alkylene oxide in the polyether.
This problem can be solved by a method for producing a polyurethane molded article, which is characterized by using a modified polyol obtained by reacting at a ratio of 1:1 to 1:1.

The greatest feature of the present invention is that the special polyisocyanate raw material (g) or (II) above is used as the polyisocyanate raw material.

The polyisocyanate composition (1) above contains diphenylmethane diisocyanate, diphenylmethane diisocyanate oligomers, and carbodiimides thereof in specific proportions.

Diphenylmethane diisocyanate content is to-yo
% by weight is required. Below 05A, the low-temperature storage stability is excellent, but the resulting foam has poor tensile properties and lacks flexibility, elasticity, and durability;
Storage stability deteriorates.

The content of the carbodiimide substance is required to be J to HiroOX amount %. Below 4t%, the resulting foam lacks low-temperature storage stability, and above μO%, the resulting foam lacks elasticity.

The (+) carbodiimide-containing polyisocyanate composition can be produced by various methods, but for example, a) diphenylmethane diisocyanate (commonly known as pure
MD process) and a mixture of diphenylmethane diisocyanate and diphenylmethane diisocyanate oligomer composition (commonly known as cruda MD process) are heated in the presence of a phosphoric acid catalyst, b) A method of directly reacting crude MD process in the presence of a phosphoric acid catalyst, etc. easily obtained.

Further, pure MD is added to the carbodiimidation composition.
If you want to use 0rudJ MD, you can mix it later.

The analysis of each component can be carried out in the following manner by using a refractometer as a detector and using Rugger permasol chromatography (commonly known as GPO).

First, a pure substance of diphenylmethane diisocyanate is used, its elution time is determined, and a calibration curve is created. Next, 4
When GPC is performed using a +J 'HJ crude MD machine, the elution time of each oligomer of diphenylmethane diisocyanate can be determined from the common pattern and the elution time of the previously obtained diphenylmethane diisocyanate. As for the carbodiimide compound, its elution time is determined based on components other than diphenylmethane diisocyanate and diphenylmethane diisocyanate oligomer. In addition, the weight (%) of each component is calculated from the @i line for diphenylmethane diisocyanate ζ, and for the diphenylmethane diisocyanate oligomer and carbodiimide form, the weight of each component (%) is calculated from the weight other than diphenylmethane diisocyanate and the area of each peak. Prolonged life by distributing it proportionately.

By the way, the modified polyisocyanate composition (li) is a polyol modified product obtained by reacting the polyisocyanate composition (1) with a special polyol. It is necessary to use a molecular weight QO of 00-f, a number of functional groups of 000, and a weight of 50 weight liters of ethylene oxide based on all the alkylene oxides in the polyether.The reaction is carried out according to a conventionally known method. The reaction is carried out by appropriately adjusting the method so that the reaction is carried out in proportion to the number of hydroxyl groups of 0.00λ to Q,/i- to each inciatate group.

If a polyol with a molecule of -2-"' or less is used, the resulting molded product will lack flexibility, and will have poor elasticity and durability. If a polyol with a ethylene content of 810% or more is used. If the molded product is too soft, it is not suitable.

In addition, when the number of reacting hydroxyl groups is 0.00λ or less, the effect of polyol modification is obtained, and when it is 0.007 or more, the incyanate group resistance is low. In both cases, good molding is achieved. I can't get a body.

The production of the polyurethane molded article is carried out by the above (1) or (II).
This can be easily achieved by reacting the polyisocyanate raw material with the polyol. As the polyol, conventionally commonly used polyether polyols and polyester polyols can be used.

Polyether polyol is water, ethylene glycol,
It is obtained by adding ethylene oxide or propylene oxide to propylene glycol, glycerin or trimethylolpropane as an initiator.
Usually, the molecular weight is 40θOx/0.000, but those with a molecular weight of 000 to Oθθ are preferable. Further, a polymer polyol obtained by copolymerizing the above-mentioned polyether polyol with acrylonitrile or styrene can also be used.

Polyester polyol is a molecule obtained from dibasic acid and polyhydric alcohol! /, 000~/5.00
0, preferably θ00 to f, 00θ.

Typical dibasic acids include adipic acid and phthalate r1.
Examples of the alcohol component include trimethylolpropane and ethylene glycol.

The catalyst may be one commonly used, and amine-based and organotin-based catalysts are used.

Examples of the amine catalyst include triethylene diamine, N-methylmorpholine, and tetramethylhexamethylene diamine, and examples of the organotin catalyst include stannath octoate, stannath oleate, dibutyltin dilaurate, and the like.

In addition, commonly used silicone foam stabilizers and crosslinking agents such as ethylene glycol and triethanolamine can also be used. Furthermore, in the present invention, it is also possible to use a foaming agent in combination to form the molded product into a foam. In that case, water and 7 Leones can be used as blowing agents. The amount of both is preferably /-j parts in the case of water and O--○ parts in the case of freon with respect to the polyol ioom.

The foam can be manufactured according to conventionally known methods.

Furthermore, in the method of the present invention, in addition to the above-mentioned polyisocyanate composition, other diincyanates such as tolylene diisocyanate can also be used in a proportion of 30% by weight or less as raw materials.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to the following embodiments as long as they do not exceed the gist thereof.

Note that the polyisocyanate raw materials used in the following Examples and Comparative Examples were obtained by the following method.

A-/nidiphenylmethane diisocyanate (hereinafter abbreviated as MDI) 63 times: ft X 1 λ (DI oligomer 3 times,
iLt+t5A, c consisting of carbodiimide body 3M foot S
rude MD work (hereinafter referred to as rough MD work)
Obtained by reacting at 260°C for ≠ hours under τ phosphor wave system.

The content of the valley component is 37% by weight of MD Koj/Shigekura S1 MD eooligomer and 1% by weight of carbodiimide body.

A-2 = MJ) I (ft crude MJ) obtained by combining the l170 heavy toy part, the MDI30 lid part, and the entire lid part, that is, M
DI7g weight ratio, &! Cruae MD (hereinafter referred to as K m M DI [21]) consisting of D eooligomer λμ* and two diimide carbodiimides was obtained by reacting at 00°C for a long time in the presence of a phosphoric acid catalyst. Something.

The content of each component is MDIjj weight %, M° C. eoligomer-λ1 weight S1 carbodiimide body 1 weight %.

A-3: Polyisocyanate raw material (Mu-7) and molecule f each θoos
A polyol having a functional group number of d and an ethylene oxide content of 02 is mixed at a reaction equivalent ratio (incyanate group/hydroxyl group) of 8010.0/, and heated at 10°C for 1 hour to complete the reaction.

A-μ nide-containing straw μθ% polyol was mixed at a reaction equivalent ratio (incyanate group/hydroxyl group)/010.0D&, and the mixture was heated at 10° C. for 1 hour to complete the reaction.

A-t: polyisocyanate raw material (A-Z), molecule: it-OO, polyol with functional group number 2, ethylene oxide content OX, and reaction equivalent ratio (incyanate group/hydroxyl group) 8 o 7 o, o y z no Mix at 4a and heat at 70°C for 1 hour to complete the reaction.

Mu-6 = Crude MDI (2) and molecular weight 6. θ00 functional group number 31 ethylene oxide-containing If, / j with the polyol of X, reaction equivalent ratio (incyanate group / hydroxyl group) /, 0 /
Mixed at a ratio of 0.0/j and heated at 1go℃ for 1 hour to complete the reaction.

The analysis of each component was carried out in the following manner using Gel Permesimin Chromatography (commonly known as GPO)'ii using a refractometer as a detector.

First, the elution time was determined using pure diphenylmethane diisocyanate, and a calibration curve was created. Next, GPO was performed using the CRU4E MD machine, and the elution time of each oligomer of diphenylmethane diisocyanate was obtained from the elution pattern and the elution time of diphenylmethane diisocyanate obtained previously. Regarding the carbodiimide compound, its elution time was determined because it was a component other than diphenylmethane diisocyanate and diphenylmethane diisocyanate oligomer. In addition, the weight fX of each component is calculated from the detection line for diphenylmethane diisocyanate, and for diphenylmethane diisocyanate oligomer and carbodiimide, the weight fraction other than diphenylmethane diisocyanate is calculated by the MB ratio of each peak. It was calculated by proportional allocation.

Example 7~μ The various polyisocyanate raw materials of A-/~A-4j were used as polyol components to form polyether polyol (
The mixture was reacted with a mixture of 10 parts of hydroxyl value λ), 1 part of water, 0 parts of amine catalyst, 0.5 parts of foam stabilizer, and 10 parts of Freon.

Incyanato index is 101.

The reaction solution was injected into a FTJLO port XμO MCXIO sub-Venus to produce a molded product. The total density was o, o jo g/7. Table 7 shows the measurement results of the physical properties of the obtained molded product.

Comparative Example 1-μ Instead of the polyisocyanate raw material of Examples 7-μ, crude MD
(1), crude MDI (2j1 polyisocyanate raw material A
A molded article was obtained in the same manner as in Example 1-P except that -j or Mu-6 was used. The measurement results of the physical properties of the obtained molded body were
/i.

As is clear from Table 1, in Examples 1 and 2, in which incyanate subjected to carbodiimidization reaction was used as a raw material,
Compared to Comparative Example 1 and JK using Crude MD Process 1 as a raw material, a polyurethane molded product with significantly improved elasticity (hysteresis loss, impact resilience) and durability (permanent set) was obtained. In other words, the molded bodies obtained in Examples 3 and μ using polyol-modified incyanato as raw materials have better flexibility, elasticity, and durability than those of Examples 1 and 1 using incyanato without polyol modification as raw materials. sex had further improved.

On the other hand, in Comparative Example 3 in which incyanate modified by using a low molecular weight polyol was used as a raw material, the obtained molded product was poor in flexibility, elasticity, and durability. In addition, even in Comparative Example D, in which polyol-modified incyanate was used as a raw material without carrying out a carbodiimidation reaction, the flexibility and elasticity of the obtained molded product were poor.

For reference, the low-temperature stability of each incyanate raw material used in Examples and Comparative Examples was measured. That is, the stability at low temperatures was evaluated by leaving each incyanate raw material in a refrigerator of total +j'c and measuring the number of days until crystal precipitation. The results are shown in Table 2.

Table 2 shows that carbodiimidation increased the low-temperature storage stability, and polyol modification further improved the stability.

〔Effect of the invention〕

According to the present invention, a polyurethane molded article that is flexible, has excellent elasticity, and durability can be easily produced using a polyisocyanate raw material that has excellent low-temperature storage stability.

Claims (1)

[Claims] In a method for producing a polyurethane molded article by reacting a polyisocyanate and a polyol in the presence of a catalyst, as a polyisocyanate raw material, (i) diphenylmethane diisocyanate, diphenylmethane diisocyanate oligomers, and these Contains carbodiimide, the content of diphenylmethane diisocyanate is 50 to 90% by weight, and the content of carbodiimide is 4 to 4.
0% by weight, and a polyisocyanate composition in which the content of diphenylmethane diisocyanate oligomer is 1 to 46% by weight; ~4. Modified polyol obtained by reacting a polyol with an ethylene oxide content of less than 50% based on the total alkylene oxide in the polyether at a ratio of 0.002 to 0.1 hydroxyl groups per isocyanate group. 1. A method for producing a polyurethane molded article, characterized by using a polyurethane molded article.