DE2559637A1 - PROCESS FOR PRODUCING A THERMOPLASTIC POLYURETHANE IN INJECTION MOLDING QUALITY - Google Patents

Description

t,: = .- ,. April 15, 1977

; > Da./kr

Per,! .... .. .- :; "c." A 137 *.

5060 ßorgiö G.ueUiii 3

McGord Corporation Detroit, Michigan / USA

"Process for the production of a thermoplastic polyurethane in injection molding quality"

The invention relates to a method for producing a thermoplastic polyurethane in injection molding quality.

Thermoplastic polyurethanes made from ELyether and polyester-polyols. The polyester polymers are

709842/0034 _ ₂ _

relatively expensive and consistently have good to excellent physical properties Properties; however, they generally have poor moisture resistance and properties low temperatures. Injectable polyether-based polymers are based on the relatively expensive PTMEG poly oils (Polytetramethyl ether glycol polyols). Conventional polymers based on PPG ether (polypropylene glycol) are suitable not for injection molding and have physical properties that make them suitable for some areas of application, e.g. for manufacturing make outer trim parts for motor vehicles unusable. The invention is based on the object of a method to create a thermoplastic polyurethane, which does not have the aforementioned disadvantages.

The invention consists in that first the graft polyol, the polyalkene ether diol and the aromatic polyisocyanate are reacted to form a prepolymer, then this prepolymer with the aforementioned Cg-Cg-alkenediol is mixed, then this mixture is poured out as a layer and hardened and that finally the layer is broken and is ground to grain size for injection molding.

The attached drawing shows schematically the preliminary stage and the stages of the process according to the invention represent.

- 3 709842/0034

- G-The procedure is explained with reference to the drawing.

First, the two polyols, namely the modified polyol through line 11 and the polyalkene ether diol (PTMEG) through line 13, introduced into a reaction vessel 10, where it is degassed and heated to 113.degree.

The aromatic diisocyanate is then fed to the reaction vessel 10 through line 12 and the mixture is added Possibility of exothermic heating to 121 ° C. Then degassing is carried out and the free isocyanate content is determined. In general the free isocyanate content is between 4 and 15, preferably between 8 and 12; in the following examples 2 and 3 it was 11, 27 and 9.55, respectively. The prepolymer can then be stored for the next step.

The short-chain diol, namely 1,4-butanediol (BDO), is separated prepared, dried if necessary and, if wax: is to be used, mixed with a wax solvent. The diol ' Mixture is then passed through line 15 and the prepolymer through line 14 of a casting machine 20 continuously at about 110 ° C supplied. After thoroughly mixing the two constituents; divide the mixture through the line 16 in a casting tub 30 | poured, which is kept at just above 99 ° C. The cast Layer can be, for example, 25 mm thick; after this ;

it has solidified, within about 4 to 5 minutes, j

can be cut into 75 x 75 mm pieces, removed!

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-V

and placed in container 40 as indicated by line 17 is. After aging for a week, the elastomer can change to a position suitable for further deformation Size can be ground and, if desired, mixed with aggregates. Alternatively, the emerging from the line 16 can Melt extruded and brought into granulate form to then be further processed into molded parts.

It has been found that adding a catalyst to the mixture in the casting machine 20 accelerates the reactions can be so that the polyurethane can be poured directly into a mold to produce the desired molded product permit. Dibutyl tin dilaurate or mercaptide can be used as the catalyst or the like can be used; the casting temperature can then be significantly lower, for example at 40 ° G, where the mold temperature is 71 to 82 ° C.

The following table contains two examples in which the process according to the invention was used.

Examples below mean:

A '= equivalent
G = parts by weight

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-B-

, AG

Modified polyol 0.5 100

PTMEG (polytetramethylene ether glycol) 0.5 28.24

MDI (4,4'-diphenylmethane diisocyanate) 6.0 85.64

BDO (1,4-butanediol) 5.02 _t 26 ,, 20

Wax 0.3 0.63

Ä G

0.75 100

0.25 9.42

6.00 57.08

5.02 17.40

0.30 0.55

Other values:
Shore hardness D (5 seconds) Tensile strength (originally) after 70 hours at 110 ° C

after 7 days at 80 ° C and 100 # rel. Humidity ^:

Elongation (originally) after 70 hours at 110 ° C after 7 days at 80 ° C and at 100? i rel. humidity

Shear strength

Stiffness (original) at 22 ° C and 2.8 cm / kp at -30 ° C and 16.8 cm / kp

after 70 hours at 110 ° C. and 2.8 cm / kp

at 71 ° C and 1.4 cm / kp

709842/0034 45 ,.,

210 kg / cm ² 184 kg / cm ²

200 (-5.0? Q 165 (

kp / cm kp / cm

(
kp / cm

537

(kp / cm2

503

4935ί (-8.25ί)

91 kg / cm 74 kg / cm

over scale 693 kp / cm end value _{or similar}

kp / cm ^ 1462 kp / cnr

above full scale

above full scale

707 kg / cm *

393

- Jb -

AWAY

Tensile value at 200 % LSngirog 62.5 5t 53.1 <f>

Peak impact resistance

(Fisher body test)

originally (no break) passage passage after 70 hours at 110 ° G

(no break) continuity continuity stretching test at 121 ° C: (4? 6 maximum) no change 1.6 #

The modified polyol was NIAX D-432 from Union Carbide Company, a polymer having a molecular weight of about 4,000 made by reacting 80% by weight of a poly (oxyalkylene) diol with a molecular weight of 2800 and 20% by weight of a 50% by weight styrene-aerylnitrile monomer mixture in the presence a free Badikal catalyst (azobisisobutronitrile) is formed, as described in Belgian patent 788 115 of the Union Carbide company. The poly (oxyalkylene) diol is produced by causing the propylene glycol to react first with propylene oxide and then with ethylene oxide so that the chains end in ethylene oxide units. The proportions are such that about 4.88 propylene oxide units Any ethylene oxide will come. When the poly (oxyalkylene) diol is brought together with the styrene-acrylonitrile monomer mixture, some of the two monomers appear to copolymerize and attach to the diol while others seem to simply copolymerize without being bound into the diol,

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-40
while they are dearly missed with it.

A polytetramethylene ether glycol (PTMEGr) with a molecular weight of 1000 was used as the polyalkylene ether diol, which is below the trade name Polymeg 1000 from Quaker Oats Company, Chemical Division, Merchandise Mart Plaza, Chicago, Illinois 60545. Polyglycol 1000 from E. I. duPont de Nemours can also be used.

The wax was an Ethelyn-Bis-stearamide, which was sold under the trade name Advawax 158 ° C by the company Cincina Ing., Reading, Ohio 45215.

named Advawax 158 ° C from Cincinatti Milacron Chemical

709842/0034

Claims (4)

: -. ■ '' ■ 15. _ r. da./kr P 25 59 637.6 McCord Corporation claims 1. Process for the production of a thermoplastic polyurethane In injection molding quality, in which the following substances are initially made to react with one another: Graft polyol 100 parts by weight Polyalkene ether diol 2-70 parts by weight aromatic polyisocyanate 40-100 parts by weight 10- 40 parts by weight, wherein the graft polyol is a copolymer having a molecular weight of 2,000 to 5,000 a) 70-90 wt .- # of a poly-Coxy-Cj-C.-Alken ^ iols with a molecular weight of 1000 to 4000, caused to react in free radical polymerization with b) 10 to 30 wt .- # of a monomer mixture of one 7098 / .2 / 0034 - Part by weight of a vinyl aromatic hydrocarbon and 0.1 to 9 parts by weight of an olefinic Cp-Cg nitrile, and wherein the polyalkene ether diol has a molecular weight between 500 and 2000, characterized in that first the graft polyol, the polyalkene ether diol and the aromatic polyisocyanate are reacted to form a prepolymer, then this prepolymer is reacted with it the aforementioned G ₂ -G ₆ -alkene diol is mixed, then this mixture is poured out as a layer and hardened and that finally the layer is broken and ground to grain size for injection molding. 2. The method according to claim 1, characterized in that that the aromatic polyisocyanate is selected from the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), 1,5-naphthalene diisocyanate, Dianiside diisocyanate (DADI), 3,3'-dimethyl-4,4'-biphenyl diisocyanate (XDI) includes. 3. The method according to claim 1 and 2, characterized in that the graft polyol consists of one Poly (oxypropylene-ethylene) diol of a molecular weight 709842/0034 between 2400 and 3200 and a 50 styrene-acrylonitrile monomer Mixture is made. 4. The method according to claim 1 to 3, characterized in that the prepolymer has a content of free isocyanate between $ 7 and $ 15. 709842/0034