JPH06322055A - Hot-melt polyurethane foam and thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a hot-melt polyurethane foam which can be easily and efficiently recovered and reclaimed and to obtain a resin composition which can give a high-quality polymer blend composed of a thermoplastic resin and the foam uniformly dispersed therein and has excellent reclaima-bility. CONSTITUTION:This polyurethane foam is produced by foaming a urethane- forming material comprising a polyol and an allophanate isocyanate having a structure having an allophanate bond and an allophanate conversion (as measured by GPC) of 40-70wt.% and has a hot-melt temperature of 190 deg.C or above. The objective resin composition is produced by kneading this foam (-0.005-10 pts. wt.) and a thermoplastic resin (100 pts. wt.) under heating to the hot-melt temperature of the foam or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-meltable polyurethane foam and a thermoplastic resin composition containing the heat-meltable polyurethane foam, and more particularly to a polyurethane foam and a thermoplastic resin composition which can be easily reused. INDUSTRIAL APPLICABILITY The present invention is used as a shock absorber for toys such as cushions, pillows, plush toys, dolls, moldings or pads, mats, etc. Widely used in.

[0002]

2. Description of the Related Art Conventional flexible polyurethane foams are widely used in composite products which are composited with a thermoplastic resin. When this composite product is heated and melted as it is to be pelletized, or when it is remolded using a thermoplastic resin molding machine according to a conventional method, both are not mixed uniformly,
Polyurethane particles float on the surface of the thermoplastic resin and separate from each other, so these polyblends cannot be obtained,
Therefore, reuse and remolding were extremely difficult. Therefore, when it is desired to separate the two, it is customary to physically or chemically separate them and use them for their respective purposes. That is, since a composite product such as a co-molded product of polyurethane foam and another polyurethane foam or a laminated product of PVC and polyurethane foam cannot be heated and melted or extruded and re-molded as it is, the foam and the thermoplastic resin are combined. There is also known a method of physically stripping, crushing the stripped foam and re-molding, or decomposing glycol by using glycol or the like to liquefy and recover as a polyol (Japanese Patent Publication No. 46-200).
69, Japanese Patent Publication No. 53-34000).

[0003]

However, in this method, the process is complicated, the recovery efficiency is not excellent, and it is economically difficult to apply. On the other hand, the thermoplastic resin is regenerated and pelletized. However, it is inevitable that the urethane solidified product floats and remains on the surface of the regenerated pellet, so that a high quality product cannot be regenerated. Furthermore, in order to compatibilize the conventional polyurethane foam with a thermoplastic resin,
Although it is heated near the melting temperature of the thermoplastic resin, this polyurethane foam does not melt, and thus it was not possible to obtain an interdispersed polymer blend even by adjusting the density, the physical properties and the like. Further, although a method for producing an alohanate polyisocyanate is known in JP-A-46-1671, it is stated that it is used to produce a heat-meltable polyurethane foam which is melted at high temperature and is excellent in reusability. Not suggested at all.

The present invention overcomes the above-mentioned drawbacks, and the heat-meltable polyurethane foam can be easily and efficiently recovered and reused, and the heat-meltable polyurethane foam is uniformly dispersed in the thermoplastic resin. It is an object of the present invention to provide a resin composition which can provide a high-quality polymer blend and is excellent in reusability.

[0005]

The present inventors have completed the present invention as a result of extensive studies on recyclable polyurethane foam and polymer blends using the same. That is, the heat-fusible polyurethane foam according to the first aspect of the present invention has a structure having an alohanate bond, and the conversion rate of the alohanate is 40 to 70% by weight.
Is produced by foaming using a urethane raw material containing alohanate isocyanate and a polyol, and has a heat melting temperature of 190 ° C. or higher.

The above-mentioned "alohanate isocyanate" has a structure in which 1 mol of isocyanate is added to urethane as shown in the following formula. RNCO ₂ R '+ RNCO (or 2 RNCO + R'O
In H) = RNHCO-N (R ) CO 2 R ' present invention, the allophanate conversion from 40 to 70
In addition to the above-mentioned alohanate bond, the bond of urethane, urea, burette and the like is included. This conversion rate of alohanate is a value obtained by GPC (gel permeation chromatography) measurement (unit:% by weight).
And is calculated by the following formula. Conversion (wt%) = [alohanate isocyanate amount (parts by weight) / total isocyanate amount (parts by weight)] × 100 If the alohanate conversion ratio of this polyisocyanate exceeds 70% by weight, the viscosity of the isocyanate will increase, Is not suitable for the production of the above, and if it is less than 40% by weight, the concentration of contained alohanate groups becomes small and the heat melting property at high temperature is lost, which is not preferable. This conversion rate is particularly preferably in the range of 45 to 60% by weight. that is,
This is because they are easily melted by heat melting or heat kneading, develop thermoplastic (melting) characteristics, and are completely compatible with the thermoplastic resin.

The types of (poly) isocyanate used are aromatic TDI, MDI, and polymeric MD.
I, NDI, PPDI, XDI, TMXDI or aliphatic HDI, H12MDI, IPDI, LDI, IP
C, hydrogenated XDI, CHDI, TODI, and modified products thereof can be used. Of these, TDI and MD
The use of I, IPDI and their variants is suitable.
In addition, the conversion of polyisocyanate to alohanate,
The desired product can be obtained by variously selecting the raw material composition, heating conditions, pressurizing conditions and the like. For example, the heating temperature is preferably 20 ° C. or higher, particularly 70 to 100 ° C.

As the polyurethane foam to be produced,
Any material may be used as long as it exhibits heat-melting property, and its type, form, etc. are not particularly limited, and for example, soft mold foam, semi-rigid mold foam, hard mold foam, etc. Its density is usually 0.005 to 1.000.

As the above-mentioned "polyol", known polyols such as polyether polyol or polyester polyol can be used. As the polyether polyol, those having a molecular weight of 1,000 to 10,000 and having two or three functional groups are preferable. Similarly, the polyester polyol has a molecular weight of 1,000 to 5,000 and has two or three functional groups.
Sensory ones are preferred.

As other compounding raw materials for producing polyurethane foam, known polyurethane plasticizers (for example, DOP, DBP, TOP etc.), foaming agents (water,
HCFC, air, nitrogen, pentane, methylene chloride, nitroalkane, formic acid, etc.), flame retardants (known phosphorous halides such as TCPP, etc.) can be used, and further, dispersants, cell open agents (polyether siloxane, Known substances such as sulfonated sodium ricinoleate) can be used.
The NCO / OH equivalent ratio (so-called isocyanate index) is preferably 70 or more, and particularly preferably 80 or more.

The thermoplastic resin composition of the second invention is obtained by heating and kneading the heat-meltable polyurethane foam of the first invention and the thermoplastic resin at a temperature higher than the heat-melting temperature of the heat-meltable polyurethane foam. It is characterized by Examples of the above-mentioned "thermoplastic resin" include acrylonitrile butadiene styrene resin (referred to as ABS) and polystyrene (P
It is called S. ), Polyvinyl chloride, polyoxymethylene,
Polyester, polyamide resin, ethylene-vinyl acetate copolymer, and modified thermoplastic resins thereof can be used. The thermoplastic resin composition blended by melting the above polyurethane can retain the thermoplastic properties as it is.

The blending amount of the above-mentioned hot-melt polyurethane foam is 0.005 with respect to 100 parts by weight of the thermoplastic resin.
It can be 10 to 10 parts by weight. With this blending amount, the above heat-meltable polyurethane foam is AB
Even when kneaded with a thermoplastic resin such as S or PS, the physical properties of the resin composition are hardly affected, and the impact resistance can be improved. In particular, in order to obtain the same physical properties as the thermoplastic resin used, 0.00
The compounding amount can be about 5 to 10 (particularly about 0.005 to 6 ). It can also be observed under an electron microscope that a polymer homogenous dispersion blend was obtained in the state of sea and island of the polymer.

Furthermore, the mixing of the thermoplastic resin and the polyurethane foam can be carried out by heating or under pressure, and for example, kneading with a kneader, extrusion kneading and the like can be all known methods. Alternatively, the mixture may be pelletized and remolded, or the resin may be directly kneaded and remolded.

Further, as shown in the third invention, a urethane raw material having a structure having an alohanate bond and having an alohanate conversion rate of 40 to 70% by weight and a urethane raw material containing a polyol and a thermoplastic resin (filling). Can also be considered as an agent.), And then kneaded by heating and kneading at a temperature higher than the heat melting temperature of the heat melting polyurethane foam produced from the above urethane raw material. You can In this case, after being used as a foam, a predetermined composition can be produced at once without adding or using other resins, which is very useful.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples. (1) Preparation of Alohanate Polyisocyanate No. 2,4-TDI was used. Five kinds of alohanate isocyanates 1 to 5 were synthesized under the following conditions, and the results are shown in Table 1. In the table, NCO%,
The viscosity and the conversion rate of alohanate are shown together. The conversion rate of this alohanate was obtained by GPC measurement (unit:
% By weight) and was calculated by the following formula. Conversion rate (wt%) = [alohanate isocyanate amount (parts by weight) / total isocyanate amount (parts by weight)] × 100 Incidentally, this GPC measurement was carried out as follows. That is, about 10 mg of the prepared alohanate isocyanate
Was precisely weighed and dissolved in 10 ml of THF (tetrahydrofuran) to adjust the concentration to 0.1% (wt / vol). The composition of this solution was examined by GPC using THF as an eluent, polystyrene gel as a packing material, and a column having a size of 8φ × 300 mm, and the amount of alohanate isocyanate was determined.

[Synthesis conditions] 2,4-Tolylene diisocyanate (2,4-TDI) under a nitrogen stream while maintaining a predetermined amount of diethylene glycol (DEG) at 70 ° C or lower.
Add to. Then, acetylacetone zinc, which is an alohanation catalyst, was added to the reaction mixture, and the reaction was carried out for a predetermined time while maintaining at 70 ° C. to obtain modified isocyanates having different NCO values. According to the results of Table 1, when the conversion rate of alohanate in each alohanate isocyanate was increased, the viscosity was increased in proportion thereto. Therefore, as a foam isocyanate, the conversion rate is 40 to 6
0% by weight (NCO%; about 30 to 26%, viscosity; about 0.5
-80 Pa · s) is suitable.

[0017]

[Table 1]

(2) Manufacture of urethane foam Each foam (comparative products No. 1 and 2, implementation products No. 3 to 1)
1) is the raw material composition shown in Table 2 (the raw material types are shown below).
Was used to produce a foam under the following foaming conditions.

[0019]

[Table 2]

[Raw material] Polyol 1: “No.38” (manufactured by Sanyo Kasei): Polyether type trifunctional 2: “N4042” (manufactured by Nippon Polyurethane): Polyester type bifunctional 3: “PL2100” (manufactured by Sanyo Kasei) ): Polyether type bifunctional chain extender 1: Ethylene Glycol 2: "KL-210" (manufactured by Mitsui Toatsu Chemicals) Catalyst 1: "LV33" (manufactured by Chukyo Yushi) 2: "Niax A-1" (manufactured by UCC) ) 3: "DABCO-XDM" (manufactured by Sankyo Air Products) Foam stabilizer 1: "SF2961" (manufactured by Toray Dow Corning Silicone) 2: "SRX294A" (manufactured by Toray Dow Corning Silicone) 3: "SZ-1946" (Japan Unicar) 4: "F-122" (Shin-Etsu Silicon) Isocyanate 1: "TDI-80" (Nippon Polyurethane) 2: "SBU-0379" (SBU) 3: Alohanate Isocyanate NO.4 (Conversion rate) 45.1% by weight) 4: Alohanate isoshi Sulfonates NO.1 (conversion: 89.8 wt%) 5: allophanate isocyanate NO.5 (conversion: 24.3 wt%)

[Foaming conditions] 100 parts by weight of polyol are added,
Calculated amount of alohanate isocyanate, water,
Mix with catalyst and foam stabilizer. The reaction mixture foamed immediately after stirring and became a foam having elasticity. Table 3 shows the physical properties of the foam produced as described above. According to this result, when alohanate isocyanate was used (N
o. The foaming was also possible in 3 to 11) as in the case of normal isocyanate.

[0022]

[Table 3]

(3) Melt Test of Foam Each of the foams produced as described above was subjected to a melt test. In this test method, a foam sliced to a thickness of 1 cm was placed on an aluminum foil in a circulation type oven controlled to the test temperature shown in Table 4, and the foam state after 10 minutes was visually confirmed. The results are shown in Table 4. The display of evaluation is x:
Not melted, Δ: partially melted, ◯: completely melted. According to these results, the comparative examples (Nos. 1 and 2) containing no alohanate isocyanate did not melt even when heated to 230 ° C. On the other hand, in Examples (Nos. 3 to 11) containing alohanate isocyanate, 190 to 2
It becomes melted by heating to 30 ° C.

A usual thermoplastic resin generally has a linear structure, but the polyurethane foam of the present invention has a branched structure but exhibits heat melting (plasticity). The melting temperature can be adjusted by the properties of the polyol to be used (polyester or polyether, its number of functional groups or molecular weight, etc.). The foam that melts at the lowest temperature is a foam (No. 3, 4) using a bifunctional polyester polyol, and then the bifunctional polyether polyol (No.
6) The melting temperature changes to a higher one depending on the polyol used, such as trifunctional polyether polyol (No. 5). Furthermore, since the mixed system (mixed system of trifunctional and bifunctional polyether polyol; No. 7) shows an intermediate melting behavior, the melting behavior is adjusted by mixing polyols having different functional groups. You can also do it. When the density is reduced (No. 8,
No. In 9), the melting temperature was increased, but the melting behavior of all foams was observed.

[0025]

[Table 4]

(4) Kneading test of polyurethane foam and thermoplastic resin Each foam (No. 1 to 3 and 5) prepared in the above (2)
~ 6) and the thermoplastic resin were kneaded by the following method.
Each foam (shown in Tables 5 and 6) was sliced into 1 cm square pieces, dried in a vacuum oven at 80 ° C. for 2 hours, and then each foam and the thermoplastic resin (ABS) shown in Table 5 [trade name; "38R" , Manufactured by Japan Synthetic Rubber Co., Ltd.] and a predetermined amount of thermoplastic resin (PS) [trade name: “IT40” manufactured by Idemitsu Petrochemical Co., Ltd.] shown in Table 6 (similarly vacuum dried). In a conical mixer for 3-5 minutes, 200
Kneading was performed at ° C. After kneading, the resin is crushed and then injection molded to obtain physical properties (tensile strength, Izod impact value,
The glass transition temperature and dispersion state) were measured. The results are shown in Tables 5 and 6. The tensile strength is JISK7113,
The Izod impact value was measured by JISK7110, the glass transition temperature was measured by JISK7121, and the dispersion state was measured by SEM observation.

[0027]

[Table 5]

[0028]

[Table 6]

When the foam was kneaded with ABS as the resin (Table 5), the comparative product had a lower strength compared to the ABS alone (original), whereas the product (3-10 p)
With the addition of bw), there was almost no decrease in strength. Further, although the Izod impact value was remarkably lowered in the comparative product, the reduction was remarkably small in the embodied product, and the difference between the two was remarkably large. Also, in the case of PS (Table 6), the same tendency was shown, but the impact value improvement as observed in a usual polymer blend was observed. This means that the product foam is improved from the viewpoint of recycling as well as the resin properties by blending [which is superior to PS alone (original). ) Also proved to be effective.

The present invention is not limited to the specific examples described above, and various modifications may be made within the scope of the present invention according to the purpose and application. That is,
The isocyanate to be used, the type of polyol, the conversion rate of alohanate, the type of thermoplastic resin and the blending amount thereof are variously selected.

[0031]

The polyurethane foam of the present invention is 190
Since it is melted by heating above ℃, it can be recovered and reused easily and efficiently. Further, in a thermoplastic resin composition comprising this thermofusible polyurethane foam and a thermoplastic resin, since this thermofusible polyurethane foam is uniformly dispersed in the thermoplastic resin, a high quality blend resin (polymer blend) It can be provided, and because it is entirely thermoplastic, it has excellent reusability.

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Claims (4)

[Claims] 1. A urethane raw material containing an alohanate isocyanate having a structure having an alohanate bond and having an alohanate conversion of 40 to 70% by weight, and produced by foaming, and having a heat melting temperature of 190. A hot-melt polyurethane foam characterized by having a temperature of ℃ or higher. 2. A thermoplastic resin composition obtained by heating the hot-melt polyurethane foam according to claim 1 and a thermoplastic resin to a temperature higher than the hot-melt temperature of the hot-melt polyurethane foam and kneading them. object. 3. A urethane raw material having a structure having an alohanate bond and having an alohanate conversion of 40 to 70% by weight and a urethane raw material containing a polyol and a thermoplastic resin, followed by foaming.
A thermoplastic resin composition obtained by heating and kneading at a temperature higher than the heat melting temperature of a heat-meltable polyurethane foam produced from the above urethane raw material. 4. The blending amount of the heat-fusible polyurethane foam is 0. 0 with respect to 100 parts by weight of the thermoplastic resin.
The thermoplastic resin composition according to claim 2 or 3, which is 005 to 10 parts by weight.