FR2495624A1 - PROCESS FOR PRODUCING INJECTION MOLDED POLYURETHANE ELASTOMERS WITH REINFORCED REACTION - Google Patents

Abstract

THE INVENTION RELATES TO THE FIELD OF MOLDED POLYURETHANES BY INJECTION WITH REACTION AND BRIEFLY CALLED POLYURETHANES MIRR. THE OBJECT OF THE INVENTION IS A PROCESS FOR IMPROVING CERTAIN PHYSICAL PROPERTIES OF MOLDED POLYURETHANE ELASTOMERS BY INJECTION WITH REINFORCED REACTION MIRR OBTAINED BY THE REACTION OF TWO CURRENTS, ONE CONTAINING POLYISOCYANATE AND THE OTHER HYROGENE CONTAINING MATIGENE. THE PROCESS CONSISTS OF INTRODUCING ALL THE INERT CHARGING MATTER INTO THE CURRENT CONTAINING ISOCYANATE BEFORE THE MIXING AND REACTION WITH THE CURRENT CONTAINING ACTIVE HYDROGEN AND THEN REACTING THE CURRENTS IN A KNOWN WAY. MIR POLYURETHANE PARTS ARE USED IN VARIOUS APPLICATIONS IN EXTERIORS OF AUTOMOTIVE BODYWORK.

Description

The present invention relates to the field of polyurethanes molded by

injection with reaction

  and briefly called MIRR polyurethanes.

  RIR is a technique for mixing and rapidly molding large urethane parts, hardening

  quickly. Polyurethane parts (MIR) are used

  in various applications in automobile body exteriors, in which their

  low weight contributes to the conservation of energy.

  Parts (MIR) are usually made of

  rapidly depositing materials containing active hydrogen with a polyisocyanate and placing the mixture in a mold where the reaction is carried out. These materials

  containing active hydrogens include a poly-

  high molecular weight polyhydroxy ether and a low molecular weight active hydrogen compound. The low molecular weight compounds containing active hydrogens are ethylene glycol,

  1,4-butanediol or similar materials

specialists.

  In general, materials containing

  high molecular weight active hydrogen

  or low are mixed with a catalyst, and possibly

  other substances, in a tank and

  and the polyisocyanate is placed in another tank.

  When the contents of the two tanks are placed in a mold, a reaction occurs and the part (MIR) is formed. In many cases, in order to improve the strength properties of the product (MIR), a reinforcing material such as cut or ground glass or other mineral fibers is incorporated into the product (MIR) by introducing the filler material. inert in the unreacted compounds. Prior to the present invention, the filler was placed on the side of the active hydrogen-containing material, i.e. the polyol side or the fraction between the polyol side and the polyisocyanate side before the polyol is mixed with the isocyanate streams. It has surprisingly been found that properties are significantly improved if the whole

  Inert charae material is introduced from the insulated

cyanate before the reaction.

  The subject of the invention is a method for

  improve certain physical properties of elasto-

  Reinforced reaction injection molded polyurethane (MIRR) mers obtained by the reaction of two streams, one containing polyisocyanate and the other containing active hydrogen materials. The process involves introducing all the inert filler material into the isocyanate-containing stream prior to mixing and reaction with the active hydrogen-containing stream and then reacting the streams in a known manner. The polyols used to make the elastomers (MIR) of the present invention include polyether polyols, polyester diols, triols, tetrols, etc., having an equivalent weight of between about 1000 and about 3000. These polyether polyols

  based on trihydric initiators having a hydro-

  between about 56 and about 54 are

  most popular. The polyethers may be made from lower alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide or mixtures of propylene, butylene and / or ethylene. To obtain fast reaction speeds generally required in the molding of polyurethane elastomers (MIR), it is necessary to

  desirable that the polyol be sufficiently covered

  ethylene oxide to increase the speed of

  reaction of the polyurethane mixture. It is preferred to use

  usually at least 50% primary hydroxyl, although lower primary hydroxyl

  to this value are acceptable if the speed of reaction

  It is fast enough to be interesting on an industrial level.

  The chain lengthening agents used

  sands in the invention include diols, amino alcohols, diamines, or mixtures thereof. Linear low molecular weight diols such as 1,4-butanediol and ethylene glycol have been found to be

  suit. Ethylene glycol is particularly

  Brother. Other chain lengthening agents among

  cyclic diols such as 1,4-cyclohexane

  hexane diol and diols containing nuclei such as bishydroxyethylhydroquinone, diols containing amide or ester functions, or amino alcohols,

  aromatic diamines and aliphatic amines

  should also be used as chain extender

in the practice of the invention.

  A wide variety of aromatic polyisocyanates, such as p-phenylene diisocyanate, polymethylene polyphenylisocyanate, 2,6-toluene diisocyanate, dianisidine diisocyanate, can be used here.

  bitolylene diisocyanate, naphthalene-1,4-diisocyanate

  nate, bis (4-isocyanatophenyl) methane, bis (3-methyl)

  3-isocyanatophenyl) methane, bis- (3-methyl-4-isocya-

  natophenyl) methane, and 4,4'-diphenylpropane diiso-

cyanate.

  Other aromatic polyisocyanates used

  In the practice of the invention, there are mixtures of methylene-bridged polyphenyl polyisocyanates having a functionality of about 2 to about 4.

  isocyanates are usually prepared by phosgena-

  The corresponding methylene bridged polyphenyl polyamides are usually obtained by reacting formaldehyde with primary aromatic amines such as aniline in the presence of hydrochloric acid and / or other acid catalysts. Known methods for preparing polyamines and

  polyphenyl polyisocyanates with corresponding methylene bridges

  from them are described in the

  literature and in many patents, for example

  in U.S. Patent Nos. 2,683,730,

  2,950,263, 3,012,008, 3,344,162 and 3,362,979.

  Methylene bridged polyphenyl polyisocyanate blends usually contain about

  20 to about 100% by weight of methylene diphenyldi

  isocyanate isocyanates, the remainder being poly-

  methylene polyphenyl diisocyanates having functional

  higher levels and higher molecular weights. As an example of these, mention may be made of polyphenyl polyisocyanate mixtures containing about 20 to

  % by weight of methylene diphenyl diisocyanate iso

  of which about 20 to about 95% by weight are

  4,4 'isomer, the remainder consisting of poly-

  methylene polyphenyl polyisocyananates of molecular weight

  Superior functionality and functionality have an average functionality of about 2.1 to about 3.5. These

  mixtures of isocyanates are known products,

  available on the market, and they may be prepared by the process described in United States Patent No. 3,362,979 issued January 9, 1968 to

Floyd E. Bentley.

  The aromatic polyisocyanate which is by far preferred is methylenebis (4-phenylisocyanate) or

  MDI, and can be used in the form of pure MDDI, almost

  prepolymer of MDI, pure MDI modified, etc. Products of this type can be used to prepare suitable elastomers (MIRs). As the pure MDI is

  a solid, and is therefore inconvenient to use.

  MDI-based liquid products are often used, and these fall within the definition of

  terms MDI or methylene bis (4-phenylisocyanate) used

  here. U.S. Patent No. 3,394,164 is an example of a liquid MDI. More material

  In general, the pure MDI modified with urétonime is also

  included in this definition. This product is prepared by heating pure distilled IDI in the presence of a catalyst. MDI product distilled pure in the presence of a catalyst. The liquid product is a mixture of pure MDI and modified MDI: 2 [OcNOC2 2 / -NCO] Catalyst O: O-O-O-C-N CH -NCO + C02 Carbodiimide O-O = CKNNC OCINQCi JN = CH2C> 2 C O: Nit3 CFE2Q NCO Uretonimine As examples of commercial products of

  this type, ISONATE 125M (pure MDI) and ISO-

  NATE 143M (MDI "liquid") from Upjohn. The amount of iso-

  cyanate used is preferably equal to the stoichiometric amount relative to all the ingredients

  of the formula or greater than the stoichiometric

metric.

  According to one embodiment of the invention

  tion, the polyiso-

  cyanate with active hydrogen-containing compounds such as polyols prior to polyisocyanate co-polymer mixing and polyois currents

to form the MIRR part.

  In another embodiment, the polyisocyanate stream may contain a quasi-prepolymer. A quasi-prepolymer is a product of the reaction of a polyoi with the polyisocyanate in

  quantity greater than the quantity of the product.

  Catalysts can be used to

  lerate the reaction. Among the most popular catalysts

  qluently used in this technique, we only quote

  amine catalysts and organometallic compounds

  lic. for example, tristylamine: N-methyl-

  morpholine, N, N, N ', N'-tetramethyl-, 3-butanediamine,

  1,4-diazabicyclo [2,2,1 octane, dibutyl dilaurate

  tyl! tain, the stannous octoate. Diocetate dioctate

  tin tylate, lead octoate, lead naphthenate,

  lead oxide, etc. Other catalysts of interest

  may be used such as tertiary phosphines, hydroxides or alkoxides of metals

  alkaline or alkaline salts.

  strong acids, salts, different metals, & c. These catalysts are well known in the art and are used for catalytic purposes, for example from 0.01% to about 5% relative to the naked weight.

reaction mixture.

  The composition --r) contains a large number of conventional ingredients such as complementary crosslinking agent catalysts, diluents, blowing agents and the like. The diluting agents can include low halogenated hydrocarbons.

  boiling point, such as trichloromonofluoro-

  methane and methylene chloride, carbon dioxide, nitrogen, etc. Other common additives can be used, such as, for example, foam stabilizers such as silicone oils or emulsifiers. The foam stabilizer may be an organic silane or a siloxane. Compounds of the formula RSi [O (R 2 SiO) - (oxyalkylene) R] 3 in which R is an alkyl group containing from one to four carbon atoms can be used, for example; N is an integer from 4 to 8; m is an integer

  between 20 and 40; and the oxyalkylene groups are

  propylene oxide and ethylene oxide.

  See for example the United States patent

3,194,773.

  The reinforcing materials of interest in the practice of the invention are those which are well known to those skilled in the art. For example, chopped or ground glass fibers,

  chopped or ground mats and / or other

  are interesting. The present invention

  does not lie in the fact that the inert fiber is inte-

  resenting, but in the process of its incorporation

  in the reaction medium. In other words, the

  The invention consists in introducing all the inert fibers or fillers into the isocyanate part before

  reaction with the part containing the active hydrogen.

  According to a particular embodiment

  most preferred, a polyether polyol of 5 500 molecular weight based on trihydric initiator is mixed.

  (hydroxyl number of about 33), ethylene glycol

  The polyisocyanate stream comprises a quapropepolymer of the above-described 5,500 molecular weight polyol and MDI liquid. The glass fibers are introduced into the polyisicyanate stream. The polyol stream

  and the polyisocyanate stream are mixed and

  are fed into a MIRR machine giving a MIRR elastomer which polymerizes at 121 ° C. after about 30 minutes.

  The following examples, given as

  limiting effect, illustrate the improvement made by

the process of the invention.

GLOSSARY OF TEPI "ES AND M4ATIERES

  THANOL SR-5505: a polyether triol with a molecular weight of 5,500 containing about 80% hydroxyl primary groups. L5430 silicone oil: a silicone glycol copolymer surfactant containing

reactive hydroxyl groups.

- Product of Union Carbide.

  THAISCAT DMDEE: Dimorpholinodiethylether.

  MISS UL-29: A standard diester thiol acid

  Picnic. The exact coefficient is not

  naked. Witco Chemical Co. product ISONATE 143L i: pure MDI socyanate modified to be liquid at crystallization temperatures of MDI. Product of Upjohn Co. L-55-0 Quasi-Prepolymer: A quasi-prepolymer formed by the reaction of equal weights of Isonate 143L and Thanol

SF-5505.

EXAMPLE 1

  16.0 parts by weight of THANOL SF-5505r were mixed with 6.44 parts by weight of ethylene glycol, 0.20 parts by weight.

  parts by weight of L-5430 fluid silicone, 0.25 parts by weight

  by weight of THANCAT DMDEE, 0.025 parts by weight of FOMREZ UL-29 and 0.015 parts by weight of dibutyltin dilaurate which was then introduced into the tank of a MIRR Accuratio VR-100 machine. 29.66 parts by weight of ISONATE 143L, 5.75 parts by weight of L55-0 quasi prepolymer and 14.6 parts by weight of 0.16 cm of Owens / Corning Fiberglass P crushed glass fibers were mixed. 117N which was then introduced into the reservoir of the machine containing the isocyanate compound. The quantity of scattered glass

  in the isocyanate compound represented 20% of the

  tomère obtained. The isocyanate compound was set at 32 ° C and the polyol compound was set at 49 ° C. The machine was set so that the isocyanate / polyol ratio was 2.18 wt. For a total flow of 27.2 kg. min. In the conditions indicated above. the compounds were run in a colliding mixture head in a 45.7 x 45.7 x 0.32 cm steel mold preheated to 71 ° C. The parts were released after 1 minute. Some of the samples were not post-polymerized while others were post-cured for 30 minutes at 121 ° C and still others at 16 ° C. The dimensions of the parts

  post-treated in the three conditions were measured

  accurately and compared to the dimensions of the mold. Thus, after conditioning for one week, the mechanical properties were obtained both parallel and perpendicular to the flow.

  compounds loaded with glass fibers in the mold.

  EXAMPLE 2 (Comparative) Example 1 was repeated except that 20% by weight of 0.16 cm OCF P117B ground glass was added to each compound (5.73 parts by weight in the polyol compound). and 8.95 parts by weight in the isocyanate compound). The loaded plates were molded exactly under the same conditions as in

  example 1, apart from the fact that the weighted ratio

  The isocyanate / polyol compound was 1.544. Is the

  polymerized and tested in

described in Example 1.

  EXAMPLE 3 (Comparative) The procedure was as in Example 1, except that all the broached glass fiber (14.6 parts by weight) was dispersed in the compound

  polyol. The loaded plates were molded exactly

  under the same conditions as in Example 1, set out in par. the fact that the weight ratio isocyanate /

  polvol compounds was 0.944. They were then poly-

  merited and tested under the same conditions.

  than those described in Example 1.

  Thus, the composition of the three elastomers described in Examples 1, 2 and 3 is exactly the same. The only difference is in the choice of compound (s) in which the glass has been dispersed

before the reaction.

  The properties of the three elastomers are described in Table 1 below. It may be noted that the properties are better with respect to the example of Example 1, wherein all the glass is in the isocyanate compound. In

  In particular, the tensile strength is improved.

  thanks to the present invention. In Table 2, the shrinkage / expansion properties of the three elastomers are a function of the annealing temperatures. It may be noted that the elastomer of Example 1 is not very affected by the temperature. Example 3, in which all the glass is dispersed in the polyol compound, shows the greatest sensitivity to temperature. In fact, when this elastomer is annealed at 163WC for half an hour (Table 2). it really dilates against the dimension of

  mold. Since it is very desirable that elasto-

  MIRR mothers are insensitive to temperature variations.

  erature, it is obvious that the elastomer of Example 1

is the best.

TABLE 1

  Properties according to the distribution of glass in the polyol and liquid isocyanate compounds

Example 1

Example 1

o

Example 2

Example 3

Example 3

Flow Direction

paral-

the the

at right

dicular

Paral- Perpen-

lele dicular

Paral- Perpen-

  tensile strength Tensile strength Kg / m3 (x] .06) Elongation, (%) Flexural modulus at 25 C, Kg / m3 (x 108) Thermal sag, overpressure 15.25 cm at 163 C for 1/2 hour 3,586 1,723 0.56

3: 1.64

1.090 0.79

3, 1.64

1,652 0.61 3.094 1.055 1.37

2,848 2,672

1,617 1,055

0.99 0.91

  : Isocyanate index = 1.02, all parts annealed for half an hour at 163 ° C.

TABLE 2

  Shrinkage / dilation according to the distribution of glass in the polyol and isocyanate compounds

Example 1

Example 2

Example 3

  Annealing conditions - No annealing -0.35 - Annealing 1/2 hour

at 121 C

-0.57 -0.24 - Annealing 1/2 hour

at 163 C

  -0.35 -0.57 -0.13 -0.35 -0.35 +0.31: The shrinkage is indicated in negative percentage (-) and the dilation is indicated in positive percentage (+) against dimensions of the cold steel mold. The data is indicated in the direction perpendicular to the flow. since it is in these conditions that the differences are the

more marked.

Fi ru a% O "i o.k

Claims (6)

  A process for manufacturing injection-molded injection-molded polyurethane elastomers reinforced with inert fillers in which   two currents react with one another, one of them   polyisocyanate and the other a   containing at least one active hydrogen, which process is   characterized in that all the inert filler is introduced into the isocyanate-containing stream prior to mixing and reaction with the hydrogen-containing stream active.   2. Method according to claim 1, characterized   rised in that the material containing hydrogen active is a polyol.   3. Process according to claim 2, characterized   in that the polyol is a polyether polyol based on a trihydric initiator having a of hydroxyl between 66 and 24.   4. The process according to claim 3, wherein   characterized in that the polyol has a molecular weight about 5,500.   5. Process according to any one of the   1 to 4, characterized in that the polyiso-   cyanate is methylenebis (4-phenylisocyanate), with   pure state or in the form of a mixture.   6. Process according to any one of the   previous indications, characterized in that the charge inert is glass.