JP2997970B2 - Gelled elastic body of polyurethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gel-like elastic material used in applications requiring elasticity similar to soft tissues of the human body, such as a human body simulated model, a rehabilitation device for restoring grip strength, a medical mat for surgery, pressure ulcers and the like. About the body.

[0002]

2. Description of the Related Art The present inventors have already made many proposals on polyurethane gels having an alkylene oxide chain. However, conventional polyurethane gels include a polyol having an alkylene oxide chain, a polyurethane polyol prepolymer, and an alkylene oxide chain. And a polyurethane polyisocyanate prepolymer having a cross-linked polyurethane gel having a cross-linked structure.

[0003]

In a conventional polyurethane gel in which a segment is made of an alkylene oxide which is liquid at room temperature, the OH / NCO value is adjusted and the ratio of the tangling chain whose terminal is blocked with an alkyl chain or the like is changed. By that
It changed the viscoelasticity of the gel. In this case, a highly viscous gel is easily obtained, but the elastic recovery is not very good. Therefore, it is unsuitable for applications requiring a gel with good elasticity that can recover quickly after stress. A method of reducing OH / NCO to approach 1.0 or a method of shortening the length of a segment may be considered, but this method is insufficient to obtain a soft and elastic gel, If it is high, it has the adverse effect of making it brittle mechanically. Therefore, it is an object of the present invention to obtain a gel-like elastic body having good elastic recovery by performing a post-crosslinking in which a polyurethane chain is newly penetrated into a mesh network of a segment of a polyurethane gel in which a conventional segment is liquid. Therefore, it can be used for the purpose of the present invention.

[0004]

The gel-like elastic body of polyurethane of the present invention comprises a polyol having an alkylene oxide chain and / or a polyurethane polyol prepolymer having an alkylene oxide chain, and a polyurethane polyisocyanate prepolymer having an alkylene oxide chain. And secondary crosslinking with a blocked isocyanate to a polyurethane gel obtained by reacting

The present invention will be described more specifically.
The polyurethane gel before the secondary cross-linking is a one-component gel which is a segmented polyurethane structured by segments of an alkylene oxide which is liquid at ordinary temperature, and is mixed with a blocked isocyanate and heated. By forming the network polymer of the internal penetration type by performing the subsequent crosslinking, a gel-like elastic body having a very high elastic force and a large deformation amount can be obtained.

Such a gel having high elasticity is obtained by mixing one or more of the polyether components represented by the following structural formulas (1) to (4) with the polyisocyanate component represented by the following structural formulas (5) to (8): One or more kinds, and the following structural formulas (9) to (1)
It is obtained by mixing and reacting the blocked isocyanate component of 0). Structural formula (1)

Embedded image (However, R1 and R2 are alkyl compounds, alicyclic compounds,
(AO) is an alkylene oxide chain. )

Structural formula (2)

Embedded image

[0008] Structural formula (3)

Embedded image Structural formula (4)

Embedded image (Where (AO) is an alkylene oxide chain and R
Is a hydrogen atom, an alkyl compound, an alicyclic compound, or an aromatic compound, and 1 is an integer of 1 or 4. )

Structural formula (5) -1

Embedded image

Structural formula (5) -2

Embedded image

Structural formula (6)

Embedded image

Structural formula (7)

Embedded image Structural formula (8)

Embedded image (Where (AO) is an alkylene oxide chain and R
Is an alkyl group, an alicyclic compound, or an aromatic compound, and 1 is an integer of 1 or 4. )

Structural formula (9)

Embedded image Structural formula (10)

Embedded image (Where (AO) is an alkylene oxide chain and R
Represents an alkyl group, an alicyclic compound, or an aromatic compound. )

The prepolymer as the polyol of the above structural formulas (1) to (4) will be described.
Is a polyurethane polyol prepolymer which is a reaction product of a polyether polyol and a diisocyanate, wherein both terminal components are a polyether polyol and both terminals are -OH groups. The diisocyanate compound used here is
These are the same as those in the polyurethane polyisocyanate prepolymer described later, for example, phenylene diisocyanate, 2,2,4-toluylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), naphthalene 1,5-diisocyanate , Hexamethylene diisocyanate (HMDI), tetramethylene diisocyanate (TMDI), lysine diisocyanate, xylylene diisocyanate (XD
I), water-added TDI, water-added MDI, dicyclohexyldimethylmethane p, p'-diisocyanate, diethyl fumarate diisocyanate, isophorone diisocyanate (IPDI) and the like can be optionally used.

Structural formula (2) is glycerol (l =
It is obtained by adding polyether polyol to 1) or sorbitol (l = 4).

Structural formula (3) is obtained by adding polyether to trimethylolpropane. Similarly, 1,2,6-hexanetriol, trimethylolethane, or pentaerythritol C (shown by the following structural formula) is used. CH ₂ OH)
₄ or polyglycerin represented by the following structural formula (n = 2
(Positive integer of ３０30) or an adduct of a polyhydric alcohol such as a partial ester thereof and a polyether polyol.

[0017]

Embedded image

Embedded image

Embedded image In this case, (AO) may be a homopolymer, a block copolymer or a random copolymer.

Structural formula (4) is a polyether polyol having an alkylene oxide chain, and both terminals have --OH
In some cases, it may be a group, or one end may be blocked with an alkyl group, an aromatic group, or the like, and can be easily obtained as a commercial product.

Next, the polyisocyanate prepolymers having the structural formulas (5) to (8) will be described. The structural formula (5) -1 shows that two molecules of triisocyanate obtained by reacting trimethylolpropane with diisocyanate are represented by ( A polyisocyanate prepolymer of structural formula (5) -2 is a tetrafunctional isocyanate which is dimerized with one molecule of AO) and uses glycerol instead of trimethylolpropane. Since this kind of tetraisocyanate cannot be obtained by the reaction of two or three molecules of (AO) with two molecules of triisocyanate, (AO)
It is necessary to finely control the reaction by reducing the amount of O) below the chemical equivalent. For this reason, unreacted triisocyanate is mixed, but if this reacts with the polyol, the size of the segmented polyurethane molecule varies, and this may act on a convenient side for controlling the hardness of the gel-like elastic body.

Structural formula (6) is obtained by reacting a diisocyanate with a polyol of structural formula (2), and is trifunctional or hexafunctional. Structural formula (7) is also similar to polyol of structural formula (3). Difunctional isocyanate is trifunctional. Structural formula (8) is a reaction product of polyether polyol and diisocyanate, and is bifunctional.

Next, the blocked isocyanates of the structural formulas (9) to (10) will be described. The structural formula (9) is obtained by reacting xylylene diisocyanate (XDI) with ethanol to eliminate the isocyanate activity of XDI. is there. Structural formula (10) is a blocked isocyanate obtained by reacting ethanol with an isocyanate group of isophorone diisocyanate (IPDI).

The blocked isocyanate compound used herein is the same as that in the polyurethane polyisocyanate prepolymer, for example, phenylene diisocyanate, 2,2,4-toluylene diisocyanate (T
DI), 4,4'-diphenylmethane diisocyanate (MDI), naphthalene 1,5-diisocyanate, hexamethylene diisocyanate (HMDI), tetramethylene diisocyanate (TMDI), lysine diisocyanate, xylylene diisocyanate (XDI), TDI with water, water MDI, dicyclohexyldimethylmethane p, p'-diisocyanate, diethyl fumarate diisocyanate, isophorone diisocyanate (I
PDI) may be reacted with a lower aliphatic alcohol such as methanol (CH ₃ OH) or ethanol (C ₂ H ₅ OH). In the case of the blocked isocyanate blocked by the lower aliphatic alcohol, the original lower alcohol generated at the secondary crosslinking reaction temperature after deblocking to form an intrusive network is convenient to evaporate. The deblocking temperature is preferably relatively low in order to prevent the original gel from being denatured by heat, and a temperature of 100 to 200 ° C. is preferably selected.

The alkylene oxide chain represented by (AO) in the above structural formulas (1) to (8) can be obtained by considering that the polyurethane gel has sufficient flexibility at room temperature.
It is desirable that almost or all of the alkylene oxide chain is a compound that is in a liquid state at room temperature. If most of them are solid, the molecular motion of the segments is small and they do not work as a dispersion medium for structuring (gelling) the system.

As the compound constituting the alkylene oxide chain, for example, polymethylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, polypentamethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol and the like can be mentioned. Of these, polyethylene glycol, polypropylene glycol, and low molecular weight polytetramethylene glycol are readily available as liquid substances at room temperature.
In addition, these copolymers, for example, a polymer represented by the following structural formula can also be used.

Embedded image

Embedded image (However, l, m, and n are integers of 1 or more.)

These copolymers are block copolymers,
Any of random copolymers may be used. Further, the segments in one prepolymer may be composed of different types of alkylene oxide chains.

The hardness measured by Asker F type hardness tester is 30 to 8
In order to obtain a polyurethane gel which is soft at 0 degrees, rich in elasticity, and excellent in flexibility, it is necessary to regulate the molecular weight of the compound constituting the alkylene oxide chain. Further, it is necessary to regulate the mixing ratio of the blocked isocyanate. If the molecular weight of the constituent segments is too low, the crosslinking density will be high, and the hardness of the polyurethane gel will exceed the above range, resulting in a gel with very poor flexibility and flexibility. In the case of a long chain having an excessively large molecular weight of the constituting segment, the ratio of the tangling chain is increased due to a low probability of the movement of the long segment and the reaction of the terminal functional group. The hardness of the polyurethane gel is less than the above range even if it is blended, resulting in a gel with very poor elastic recovery.

An appropriate molecular weight range is about 150 to 1000 for polyethylene glycol, and more preferably about 300 to 800. Even when the molecular weight is tens of thousands, the range of use is wide in the case of liquid polypropylene glycol or polybutylene glycol.
Those having a molecular weight of about 3000 are preferably used.
In the case of polytetramethylene glycol, a polymer having a molecular weight of about 200 to 1,000, preferably about 400 to 800 is used because the polymer becomes a solid when the degree of polymerization is large. Further, in the case of these copolymers, those having a molecular weight of hundreds to thousands are used.

Next, the reaction ratio between the polyol component and the polyisocyanate component will be described. Empirically speaking, the polyurethane gel-like elastic material constituting the present invention has a relatively bulky structure molecule having an appropriate molecular weight and a freely movable segment length or linear terminal. Needs to have a molecule that can move freely. Therefore, if each of the polyol and the polyisocyanate is a single compound, it is necessary that one of the compounds is a combination of compounds having two functions and the other is a combination of compounds having three or more functions. If either one is monofunctional, it will not be linked, and if it is bifunctional, it will be a linear molecule, which is not appropriate. That is, either one is bifunctional and the other is trifunctional or more polyfunctional, or a combination of three or more is good. However, the reaction product of each having too large a functional number has a high network chain concentration, so that a long liquid segment is required for gelation. However, the length of the segment is limited due to the probability of response. The number of functional groups for easily obtaining a gel-like elastic body is a combination of 2 to 4, and in particular, a combination of bifunctional and trifunctional is easily adjusted in the composition. In this case, in order to finely adjust the hardness and other physical properties of the gel-like elastic body, one having a single functional group can be used for the purpose of a tangling chain having an internal dispersion medium effect. When the polyol or polyisocyanate prepolymer has only a very long (AO) chain, a polyfunctional polyhydric alcohol or a polyvalent isocyanate (both having no (AO) segment) may be mixed. By adjusting the form of the mesh chain, it may be devised to obtain a gel-like elastic body.

The reaction ratio of each prepolymer of polyol and polyisocyanate can be regulated by the ratio of terminal functional groups, that is, the value of OH / NCO. Unreacted -N
OH / NCO must be greater than or equal to 1 as post-reaction occurs if CO is left.

However, the gel in the present invention can be post-crosslinked with a blocked isocyanate so that the ratio of functional groups for the original gel alone can be larger than that of the original gel. It is selected in the range of 5.0.

Further, the mixing ratio of the blocked isocyanate will be described. By heating the blocked isocyanate, the isocyanate group becomes active again and crosslinks with the polyol component. This crosslinking results in a gel having the desired elasticity. That is, since a polyol component that reacts when the isocyanate group becomes active is required, the OH / NCO ratio of the gel obtained after the secondary crosslinking of the blocked isocyanate must be 1 or more. However, if too many blocked isocyanates are mixed and reacted, the crosslink density increases, the hardness increases, and the flexibility and flexibility deteriorate. Empirically, 1/10 to 3 / mol of the number of moles of the residual polyol in the initial reaction gel.
By mixing the isocyanate mole number of the blocked isocyanate corresponding to 4, a gel-like elastic body having desirable hardness, elastic modulus, flexibility, and flexibility was obtained.

As a reaction catalyst between the polyol and the polyisocyanate, the reaction rate can be increased by adding an appropriate amount (about 0.01 to 1.0%) of a tertiary amine such as dibutyltin dilaurate, trialkylamine or triethylenediamine. May be adjusted.

[0033]

The polyurethane gel-like elastic material of the present invention is obtained by reacting a polyol having an alkylene oxide chain and / or a polyurethane polyol prepolymer having an alkylene oxide chain with a polyurethane polyisocyanate prepolymer having an alkylene oxide chain. Since it is an internally penetrating crosslinked product obtained by secondary crosslinking of a blocked isocyanate to a polyurethane gel material, the crosslinking density can be adjusted so that excessive crosslinking does not occur, and it has appropriate elasticity and hardness. Is also excellent in flexibility. And it closely resembles the physical properties of soft tissues of the human body. Therefore, not only a pseudo model of a human body but also an elastic body capable of dealing with many physical properties, such as those used by people with mild gripping difficulty to severe people, can be provided, which is extremely useful as a rehabilitation device. Further, when the elastic body is used for a mat or the like for suppressing the occurrence of pressure ulcers, it has a moderate softness, but it does not have the fragility as in the past, so even if it is used for a long time, it will lose its shape. There is almost no. In addition, there is no bleed-out of water or oil unlike a commercial product. Further, by adjusting the type and molecular weight of the alkylene oxide chain and the type of the blocked isocyanate of the gel-like elastic material of the present invention, the Asker F-type hardness can be increased to 30%.
Elasticity of 30-250kg / cm2 within the range of -80 degrees
Which has the extremely desirable flexibility and elastic recovery ability.

[0034]

【Example】

Example 1 Polyether polyol having 11 moles of a PEG-PPG-PEG block copolymer (molar ratio 1: 2: 1, Mw: 2200) in which both ends of polypropylene glycol are bonded to polyethylene glycol and 1.1 parts of an antioxidant Against
Propylene glycol was added to glycerin, xylylene diisocyanate (XDI) was reacted, 10 moles of triisocyanate (Mw: 1600), 0.2 part of dibutyltin laurate as a catalyst were added, and blocked isocyanate (XDI-EtOH) was further added. And stirred well.

This mixture was completely defoamed under reduced pressure, placed in a mold, and left at 60 ° C. for 24 hours to obtain a polyurethane gel. Further, this gel was left in an oven at 150 ° C. for 4 hours to react with the blocked isocyanate to obtain a target polyurethane gel-like elastic body. Its final OH / NCO ratio is 1.3.

The hardness of this gel-like elastic body is from 60 degrees to 8 when comparing before and after the blocked isocyanate reaction.
At 0 degree, the elastic modulus is from 90 kg / cm ² to 240 kg / c
m ² and the elastic recovery was greatly improved. But,
Flexibility and flexibility remained unchanged without change. Example 2

Polyethylene glycol (Mw: 600)
Was added to 100 parts by weight of an antioxidant, glycerin and polypropylene glycol, and then reacted with isophorone diisocyanate to obtain a triisocyanate (M
w: 1564), 0.1 part by weight of dibutyltin laurate as a catalyst, and blocked isocyanate (XDI-EtOH) were further added and mixed, and a polyurethane gel was obtained in the same manner as in Example 1. . The gel was further left at 160 ° C. for 5 hours to react with blocked isocyanate to obtain a polyurethane gel-like elastic body. The final OH / NCO ratio of this gel is 1.5.

When this gel-like elastic body is compared before and after the blocked isocyanate reaction, the hardness is from 40 degrees to 114 degrees and the elastic modulus is from 70 kg / cm ² to 260 kg / cm ^2.
Each has been greatly improved. Flexibility maintained an excellent state without being impaired.

[0039]

As is apparent from the above description, the gel-like elastic body of the polyurethane of the present invention can be applied to the soft tissue of the human body by the conventional segments penetrating a new crosslinked body into the liquid polyurethane gel network. It can provide a new gel having similar physical properties, and is a material suitable for a simulated human body model, a rehabilitation device for grip strength recovery, a medical mat, and the like.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Shikinami 2-3-113 Azuchicho, Chuo-ku, Osaka City Inside Takiron Co., Ltd. (56) References JP-A-55-120621 (JP, A) 1-304109 (JP, A) JP-A-1-249820 (JP, A) JP-A-51-13891 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/10 , 18 / 48,18 / 83 A61L 27/00

Claims (1)

(57) [Claims] 1. A polyurethane gel obtained by reacting a polyol having an alkylene oxide chain and / or a polyurethane polyol prepolymer having an alkylene oxide chain with a polyurethane polyisocyanate prepolymer having an alkylene oxide chain is mixed with a block isocyanate. A gel-like elastic body of polyurethane characterized by being cross-linked.