DE3134491A1 - "METHOD FOR PRODUCING POLYURETHANE ELASTOMERS" - Google Patents

Description

Müller, Schupfner & Gauger patent attorneys

Karlstrasse 5

2110 Buchholz / Nordh.

August 26 , 1981

T-023 81 DE
D 75,890-F

KB (KRP)

TEXACO DEVELOPMENT CORPORATION

2000 WESTCHESTER AVENUE WHITE PLAINS, N.Y. 10650

UNITED STATES.

Process for the production of polyurethane elastomers

Müller, Schupfner & Gauger patent attorneys

Texaco Development Corp. T-023 81 DE KB D 75,890-F (KRP;

Process for the production of polyurethane elastomers

The present invention relates to the production of reinforced polyurethanes by injection molding.

The reaction injection molding process = RIM) is a process for the rapid mixing and molding of large, fast-curing polyurethane parts. RIM polyurethanes are used to manufacture a wide variety of body panels for motor vehicles used where their low weight helps to save energy. RIM parts are generally made by Mixes active hydrogen-containing materials and polyisocyanate and pours the mixture into a mold, in which then the implementation takes place. These active hydrogen containing materials consist of a polyhydroxy polyether high molecular weight and an active hydrogen-containing low molecular weight compound The low molecular weight compounds containing active hydrogen are ethylene glycol, 1,4-butanediol or similar materials that comply with the Are known to those skilled in the art. Usually the active hydrogen containing materials, both high, as well as with low molecular weight, with a cat-

lysator and any other material mixed in one container, while the polyisocyanate is in one another container is located. If these two components are brought together in one form, it becomes a reaction achieved and thus manufactured the RIM product. A reinforcing one is often used to improve strength properties Material, e.g. chopped or ground glass or other mineral fibers incorporated into the RIM formulation, by adding the inert filler material to the unreacted components. It used to be the filler material placed in the component containing the active hydrogen-containing material, i.e. in the polyol part or partly in the polyol component, partly in the polyisocyanate component before the polyol and polyisocyanate components are mixed together.

Surprisingly, it has now been found that the properties can be significantly improved if all of the inert filler material is converted into the isocyanate part is entered.

The present invention relates to a method for Improvement of certain physical properties of inert fiber reinforced RIM polyurethane elastomers according to the Injection molding process by means of the reaction of two streams, one of which is a polyisocyanate, the other of which is active Contains hydrogen containing materials «,

-Γ-

The procedure affects the input of the entire inert Filler material in the isocyanate-containing stream prior to mixing and reaction with the active hydrogen-containing Electricity and the subsequent conversion of the currents in a conventional manner.

The polyols suitable for the process according to the invention are polyether polyols and polyester diols, triols, tetrols, etc. with an equivalent weight of about 1000 to about 3000. Polyether polyols based on trihydroxy starter compounds which have a Have hydroxyl numbers from about 56 to about 2f. The polyethers can be made from lower alkylene oxides, such as ethylene oxide, propylene oxide, Butylene oxide or mixtures of propylene oxide, butylene oxide and / or Ethylene oxide are produced. To achieve the rapid implementation required for molding RIM polyurethane elastomers is normally necessary, the polyol is preferably still at a rate to increase the rate of reaction of the polyurethane mixture is added a sufficient amount of ethylene oxide. Usually at least 50% are primary Hydroxyl groups, although lesser amounts of primary hydroxyl groups are acceptable if the rate of reaction is low is large enough for industrial use.

-M-

The chain extenders suitable for the process according to the invention are preferably difunctional. Mixtures of di- and tri-functional chain extenders are also available suitable for the present invention. The chain extenders suitable for the present invention are diols, amino alcohols, diamines or mixtures thereof. Low molecular weight linear diols, such as. B. 1,4-butanediol and ethylene glycol are for the present Invention also suitable. Ethylene glycol is particularly preferred. Other chain extenders, e.g. B. cyclic. Diols, such as ζ. B. 1, ^ - Cyclohexanediol, containing rings Diols such as B. Bishydroxyäthylhydroquinon, amide or Ester-containing diols, amino alcohols, aromatic diamines and aliphatic amines are in the practice of the invention also suitable as a chain extender.

A wide variety of aromatic polyisocyanates can be used. Typical aromatic polyisocyanates are z. B. p-phenylene diisocyanate, polymethylene polyphenyl isocyanate, Toluene-2,6-diisocyanate, dianisidine diisocyanate, Bitolyl diisocyanate, naphthalene-1, ^ - diisocyanate, bis (4-isocyanatophenyl) methane, Bis (3-methy1-3-isocyanatophenyl) methane, bis (3-methyl-4 - isocyanatophenyl) methane and 4,4 · '-Diphenylpropane diisocyanate.

Other aromatic polyisocyanates suitable for the practice of the present invention are methylene crosslinked polyphenyl polyisocyanate mixtures with a functionality of about

-Sr-

Z to about 4. The latter isocyanate compounds are generally by. Implementation of the corresponding methylene-crosslinked polyphenyl polyamines prepared in the conventional manner by reacting formaldehyde with primary aromatic amines, such as aniline, in the presence of hydrochloric acid and / or other acid catalysts, with phosgene. Known processes for preparing polyamines and corresponding methylene-crosslinked polyphenyl polyisocyanates are described in the literature and for example in US Patents 2 683 73o, 95o 2 263, 3 o12 oo8, 3 3hh 162 and 3,362,979.

Usually contain methylene-crosslinked polyphenyl polyisocyanate mixtures 2o to I00 wt. ° / o methylene diphenyl diisocyanate isomers, the rest being polymethylene having higher functionalities and higher molecular weights. Typical representatives are polyphenyl polyisocyanate mixtures with 2o to I00 wt. ° / o methylene diphenyl diisocyanate isomers, of which 2o to 95 wt. ° / o the 4,4'-isomer, the remainder being polymethylene polyphenyl polyisocyanates of higher molecular weight and an average functionality of about 2 .1 to about 3.5. These isocyanate mixtures are known, commercially available materials and can be prepared by the process described in U.S. Patent 3,362,979.

The most preferred aromatic polyisocyanate is methylene bis (4-phenyl isocyanate) or MDI, in the form of, for example, pure MDI, quasi-prepolymers of MDI, modified pure MDI, etc. Materials of this type can be used to make suitable RIM elastomers. Since pure MDI is solid and therefore often inconvenient to use, liquid products based on MDI are often used. These are included here in the terms MDI or methylene bis (4-phenyl isocyanate). US Pat. No. 3,394,16k describes the use of a liquid MDI product. Uretonimine

313A491

modified pure MDI is also included. This Product is made by heating pure distilled MDI in the presence of a catalyst. The liquid product is a mixture of pure MDI and modified MDI:

2 OCN

catalyst

-NCO]

-NCO + CO,

CH,

Carbodiimide

-N-C = N

CH.

NCO

Uretonimine

Examples of commercial materials of this type are ISONATE ® J25M (pure MDI) and ISOHATE® ÜA3L (liquid MDI) by Upjohn. An amount of isocyanate is preferably used which corresponds to the stoichiometric amount based on all constituents corresponds to the composition or is greater than this.

According to one embodiment of the invention, the polyisocyanate not allowed to pre-react with any active hydrogen containing compounds such as polyols, before the polyisocyanate stream with the polyol streams is mixed, producing the RIM part.

-r-

According to a further embodiment of the invention, the poly-

Isocyanate stream contain a quasi-prepolymer. A

Quasi-prepolymer is the reaction product of a polyol with more than the stoichiometric amount of polyisocyanate.

Catalysts can be present to aid the implementation

to accelerate. Among these catalysts mostly used in this field are the amine catalysts and ^{organometallic} compounds, such as * · ΰ · trimethylamine, N-methylmorpholine, N, N, N ', N'-tetramethyl, 1,3-butanediamine, 1, 4 — Diazabicyclo [* Z, 2.1 J octane, dibutyltin dilaurate, tin (II) octoate, dioctyltin diacetate, lead octoate, lead naphthenate, lead oleate, etc. Other known catalysts, such as e.g. Tertiary phosphines, alkali and alkaline earth hydroxides or alkoxides, acidic metal salts of strong acids, salts of various metals, etc. These catalysts are well known in the art and are supplied in catalytic amounts, e.g. from 0.001% to about 5% based on the weight of the reaction mixture.

The RIM composition includes a number of others known components, such as additional crosslinkers, catalysts, chain extenders and blowing agents. Propellants are e.g. halogenated low-boiling hydrocarbons, such as trichlorofluoromethane and methylene chloride.

3134431

Carbon dioxide, nitrogen, and the like can also be applied.

Other conventional additives can also be used, such as foam stabilizers, also known as silicone oils or emulsifiers. The foam stabilizer can be an organic silane or siloxane. It can e.g. B. Compounds with the following formula can be used:

0- (R ₂ SiO) _n - (oxyalkylene) _m R

where R is an alkyl radical having 1 to 4 carbon atoms, η 4 to 8 and m 20 to 40, and the oxyalkylene groups are derived from propylene oxide or ethylene oxide. See e.g. B. U.S. Patent 3,194,773.

The reinforcing materials suitable for the method of the invention are those known to those skilled in the art are known and appear suitable, e.g. B. chopped or ground glass fibers, chopped or ground Textile fibers and / or other mineral fibers. The inven- ' This depends not on which inert fiber is suitable, but on the method of entering it in the reaction medium. The invention contemplates adding the total amount of inert fibers or fillers to the isocyanate portion. before, before the reaction with the active hydrogen-containing part. ....

According to a particularly preferred embodiment of the invention, a polyether polyol with a molecular weight of 5500 based on a trihydroxy starter compound with a hydroxyl number of about 33, ethylene glycol, liquid silicone and catalysts are mixed which make up the polyol stream Quasi-prepolymer of the polyol with a molecular weight of 5500 as described above and liquid MDI. Glass fibers are introduced into the polyisocyanate stream. The polyol stream and the polyisocyanate stream, and introduced into an injection molding (RIM) machine for the reaction, resulting in the formation of a RIM elastomer which is cured for about 30 minutes at ⁰ C 121.11.

The following examples illustrate the improvements that can be achieved by the method according to the invention.

Example 1

THANOL® SF-5505 Ethylene Glycol L-5430 Silicone Fluid FOMREZ (R) UL-29 Dibutyltin Dilaurate

16.0 parts by weight

6.44 parts by weight

0.20 parts by weight

0.025 parts by weight

0.015 parts by weight

were premixed and placed in the polyol component work container of an Accuratio VR-100 Injection Molding (RIM) machine entered.

ISONATE ® 143L L 55-0 quasi prepolymer Owens / Corning fiberglass P 117B 1/16 " ground glass fibers

29.66 parts by weight 5.75 parts by weight

YES, 6 parts by weight

were premixed and added to the machine's isocyanate component work container. The proportion of the glass distributed in the isocyanate component was 20% of the resulting elastomer. The isocyanate component was adjusted to 32.2 ° C and the polyol component of from 4 to 8.9 "C ^0. The machine was set so that the weight ratio of isocyanate to polyol 2.18 at a total output of 27.216 kg / min.

Under the above conditions, the components were passed through an impact mixing nozzle into a pre-heated to 71 ° C. Steel mold (45.7 * 45.7x0.32 cm) injected.

The parts were demolded in 1 minute. Some of the samples received no post cure _} while others received 30 minutes
at 121.C ,, and others were cured at 163 ⁰ C again. The dimensions of the parts post-treated under these three conditions were precisely measured and compared with the dimensions of the mold.

Then after a week of conditioning they became mechanical Properties achieved, both in parallel, as also perpendicular to the flow of the components reinforced with glass fibers into the mold.

Example 2 - comparison -

The formulation of the first example was repeated,
except that in this case 20% by weight of OCF P 117B 1/16 ¹¹ ground glass was added to each component
(5.73 parts by weight in the polyol component and 8.85 parts by weight in the isocyanate component).

The reinforced plaques were under exactly the same
Conditions molded as in Example 1, in which case only the weight ratio of isocyanate to polyol component was 1.544. These were made accordingly

hardened under the conditions set out in the first example and checked.

Example 3 - comparison -

The formulation of the first example was repeated, in this case all being milled Glass fibers (14.6 parts by weight) in the polyol component were distributed. The reinforced plaques were molded under exactly the same conditions as in Example 1, in this case the weight ratio of isocyanate to polyol component was 0.94-4-. These were cured and tested according to the conditions set out in Example 1.

Therefore, the composition of the three elastomers described in Examples 1, 2 and 3 is exactly the same The only difference between them is in which component or components the glass is in front of Implementation was distributed.

^; ■:; ·; 313U91 ζ

-VS-

Table I shows the properties of the three elastomers _β. It should be noted here that the elastomer of Example 1 has the best properties, namely where all of the glass is distributed in the isocyanate component.

In particular, the method according to the invention

the tensile / tear strength improves. In Table II the

Shrinkage and expansion properties of the three

Elastomers as a function of temperature treatment shown. It should be noted that the elastomer of Example 1 is least affected by the temperature. Example 3, where all of the glass in the 'polyol compo-

nente is distributed shows the greatest sensitivity

versus temperature. This elastomer is used for 1/2 hour Treated 163 ° C (Table II), it expands against the

Dimensions of the shape. As it is very desirable that RIM elastomers insensitive to temperature fluctuations it is clear that the elastomer of Example 1 is the best.

TABLE I.

Properties as a function of the distribution of glass fibers in the polyol and isocyanate components

Direction of flow

Tensile / tear strength
bar

Elongation at break %

Example

1 ©

Parallel perpendicular

352 42

310

48

Example 2 ^ Example 3 ®

Parallel perpendicular parallel perpendicular

303

64

279

30th

262

65

Bending module bar

at 25 ° C 16890

Heat deflection, cm

1/2 h at 163 ⁰ C 0.5388 15.24 cm overhang

10690

0.7874

16200

10340

1.3716

15860

0.9906

10340

0.9144

© Isocyanate index = 1.02, all parts treated at 163 ° C for 1/2 hour.

313U9T

Tables *

Shrinkage / expansion ^ as a function of

the distribution of glass in the polyol and isocyanate

Components

Example 1 Example 2 Example 3

Treatment conditions -0.35 -0.35 -0.35 No temperature
treatment -0.57 -0.57 -0.35 Temperature treatment
1/2 h at 121 ° C. -0.2 * -0.13 +0.31 Temperature treatment
1/2 h at 163 ^° C

© Shrinkage is shown as a minus% (-) and expansion is shown as a positive% (+) versus cold steel X-form dimensions . The values are shown in the direction perpendicular to the direction of flow, as there are differences on the most stand out.

Summary of abbreviations and materials

THANOL

SF-5505

L5430 silicone oil

THANCAT (R) DMDEE FOMREZ (R) UL-29

ISONATE (R) 143L A polyether triol with a molecular weight of 5500, which contains about 80% primary hydroxyl groups

A SiIi con g Iy co 1-Co poly me r-Ten sid with reactive hydroxyl groups Manufacturer: Union Carbide

Dimorpholine diethyl ether

A tin (IV) diester of a thiol acid. The exact composition is unknown.
Manufacturer: Whitco Chemical Co.

Pure MDI isocyanate modified in this way is that it is still liquid at temperatures at which MDI crystallizes. Manufacturer: Upjohn Co.

Quasi-prepolymer L-55-0 A quasi-prepolymer produced by reacting equal amounts of ISONATE φ 143L and THANOL ® SF-5505

Claims (4)

Claims 1. Process for the production of polyurethane elastomers by the reaction injection molding process, which by inert filler material are reinforced by polyisocyanate, especially methylene bis (4-phenyl isocyanate), and active hydrogen-containing materials are reacted with one another, characterized, that all of the inert filler material in the isocyanate component is entered before this is mixed with the active hydrogen-containing component and is implemented. 2. The method according to claim 1,
characterized in that poly-ols are used as active hydrogen-containing materials. 3. The method according to claim 2,
characterized in that polyether polyols which are based on trihydroxy starter compounds and have a hydroxyl number in the range from about 56 to about 24 and preferably have a molecular weight of about 5500 are used as polyols. 4. The method according to any one of the preceding claims, characterized in that that glass fibers are used as the inert filler material.