FR2704551A1 - Polymeric molded articles made of casting resins and having a metallic and possibly colored surface. - Google Patents

Abstract

The invention relates to polymeric molded articles made of highly charged casting resins and a coating containing a pearlescent pigment, having a metallic shiny and optionally colored surface, as well as to a process for preparing the polymeric molded articles, to which one applies on a surface of the forming mold, before introduction of the casting resin, a curable coating of a varnish composition L containing a pearlescent pigment, then, after the coating film has dried, the casting resin is introduced into the mold , it is polymerized by heating, then it is demolded.

Description

The invention relates to polymer molded articles,

  made of highly loaded casting resins, present

  as a metallic shiny surface, possibly colored, the surface effect being produced and fixed using a lacquering. It is already described in German patent N 693 824 that it is possible to incorporate layers containing a dye in polymer molded objects, obtained in the mold by polymerization, and this just below the surface, if applied on the wall of the mold these layers containing a dye, and which contain a solvent which is practically insoluble in the compounds to be polymerized, the polymerization then being carried out in a manner known per se, after installation

  liquid compounds to be polymerized.

  The layers containing a dye can be

  distributed uniformly or not uniformly, and pre-

  feel in the form of several colors, for example if

  different layers containing a dye are used.

  It is also planned, among other things, to use (organic) solvents for the binders used. On the other hand, it becomes useless to carry out a postprocessing, such

  than applying a cover layer.

  The publication DE-A 30 23 964 describes a process for producing areas containing a dye in acrylic and methacrylic resins, in the vicinity of the surface, and during the polymerization of the monomers and prepolymers forming the resins, in polymerization chambers formants, characterized in that firstly, in the form of a layer, dyes distributed in a homogeneous manner in a binder are applied to the wall of the forming polymerization chamber, the binder being soluble, or for the less able to swell, in the liquid resin or in its precursors, and in that, after the monomers and / or prepolymers to be polymerized, they are polymerized into resins of a

in a manner known per se.

  According to EP 061 245, a process is known for forming

  sea a molded object, in which the composition is hard-

  in a mold comprising at least two parts which

  define a cavity, and in which, before intro-

  coating the curable composition in the mold cavity, at least part of the surface forming the mold cavity receives a deposit of a material which, with

  the curable composition achieves a color contrast

  their, the deposit being predefined on the surfaces of the mold which correspond to the surfaces of the hardened molded object on which it is a question of achieving a color contrast, and which is characterized in that the deposit consists of at least one finely divided pigment, mixed with at least one finely divided filler having an average particle size of 100 µm or less, and the mixture is applied as a

  suspension in a volatile support material.

  EP-A 0 217 544 describes a process for manufacturing molded objects from curable compositions, with surface areas presenting contrasts

  colored, a surface of the mold being, before introduction

  tion of curable compositions, coated with a colo-

  rant comprising a) at least 25% by weight of a liquid support, containing 0 to 100 parts by weight of a polymerizable liquid and 100 to 0 parts by weight of an organic non-polymerizable liquid, b) from 0.1 to 10% by weight of an inorganic pigment or from 0.0001 to 1% by weight of organic dyes, c) from 0 to 60% by weight of a finely divided filler, d) from 0.1 to 50% of a drying alkyd resin soluble in the support

  a), and e) of a liquid-soluble polymer.

  EP-A O 526 818 discloses a process for preparing polymeric molded articles from resins

  heavily loaded with superficial zones

  differing from one another by their color

  their, method in which a surface of the forming mold is, before introduction of the casting resin, coated with a curable coating consisting of a composition

  containing a dye, so that it creates a different

  renciation in terms of color, the coating being applied in at least two stages of lacquering on the surface areas of the mold provided for this purpose, and, after drying of the lacquer films, the mold is filled

  casting resin, which is polymerized by heating

fage and finally unmolded.

  Particular pigmentary coloring can be obtained

  lier for example printing inks or varnishes, if pearlescent pigments are used, which are also called pigments with decorative effects. The pearly effect, which is a metallic shine, is particularly appreciated

in decorative applications.

  You can make an acrylic glass with a shiny effect.

  lant if, as is customary, a pearlescent pigment is introduced, for example by dilution, into the methyl methacrylate composition to be polymerized. However, with this conventional procedure, we cannot, from

  heavily loaded systems, get hardened objects present

  both surfaces whose metallic shine is due to

a pearly pigment.

  The invention is aimed, after the discovery of a manufacturing process making it possible to obtain them, objects, produced from highly charged hardened systems, and having a surface whose metallic shine is due to a pearly pigment. These objects, obtained from a casting resin, are of some interest, especially in the sanitary field. For this purpose, they must be provided with a surface layer, having a uniform metallic shiny appearance, and having a sufficient color or pigment thickness to counteract bleaching under the effect of moisture.

(in English: "Water-Whitening").

  According to the invention, new objects can be prepared from hardened and highly charged casting resins having surfaces with metallic shine.

  and with surface coloring thanks to the pearlescent pigment.

  Thanks to their properties, they perfectly meet the requirements to which they are subjected. It has surprisingly been found that the new objects, uniformly colored on the surface, can be prepared by relying on the process, known from EP-A 0 526 818, making it possible to produce molded polymeric objects from casting resins and having surface areas

  distinguished from each other by their color.

  To this end, the invention relates to polymerized molded articles obtained from very strong casting resins.

  charged, and having metallic shiny surfaces

  that, characterized in that the surface with shiny metal-

  lique is a coating containing a pearlescent pigment. The

pearlescent pigment can be colored.

  The invention further relates to a method for manufacturing the novel polymeric molded articles from

  heavily loaded casting resins with

  metallic glossy sides, possibly colored, characterized in that it is applied to a surface of the

  mold forming, before introduction of the coating resin

  lée, a composition of varnish L, curable and containing

  nant a pearly pigment, and, after drying of the layer of varnish, the casting resin is introduced into the mold,

  polymerization is carried out by heating and final-

  we unmold. Preferably, those which belong to the class are used as casting resins.

acrylic resins.

  Optionally, and in addition to the varnish L containing the

  pearlescent pigment, we still use, to make the

  face, another L 'varnish, without pearlescent pigment, but charged. The method according to the invention makes it possible to produce surfaces with metallic gloss as has already been

  said, of a lacquering obtained in at least one step, and even

  in two stages. In the main stage of

  lacquering, we use a dispersion of varnish L addition-

  born from a pearly pigment. To make the dispersions of varnish L and optionally of L ′, a binder B and liquid support constituents T are also used. The pearlescent pigments which should be used in the process according to the invention to form the surfaces to be

  metallic shine of new polymer molded objects

  res, are white and colored pearlescent pigments based on mica or titanium dioxide or even iron (III) oxide, with a particle size between 0.1 and approximately 50 μm. As known pearlescent pigments, for example, on a technical scale, pigments of the brand Iriodin (R) are used. They are used in printing inks, to color plastics in the mass

  and in varnishes, for example for automobiles.

  The color effect of these pigments is achieved by

  absorption of light and through interference.

  Pearlescent pigments having a certain thickness of par-

  ticles meet the interference conditions and pre-

feel iridescent colors.

  With the Iriodin (R) 9111 Rutil Feinsatin WR, according to the invention, a polymer molded object is obtained, the surface of which has a uniform metallic effect, very

  shiny and silver in color. If we use the pig-

  red Iriodin (R) 9514 Silkrot WR II, we get,

  after demoulding of the polymerized object, a surface pre-

  feeling a very shiny and red metallic effect

dark.

  In general, the pearlescent pigment G or the filler F and the binder B are used in proportions of 1: 1 to: 1 parts by weight and preferably from 2: 1 to 10: 1 parts by weight. As a first approximation, the binders B that can be used are subdivided into polymer binders (BP) and reactive binder systems (BR) (cf. H. Wagner & HF Sarx, Lackkunstharze, Carl Hanser Verlag, Munich 1959), which are soluble in the constituent

  support T. Polymer binders B-P can advantageously-

  belong to the same class of polymers as the actual casting resin. We choose them by

  example in the group of poly (meth) acrylates, in particular-

  poly (methyl methacrylate) and its copolymers

  res. As a general rule, the molecular weight Mw of the polymeric binders is between 10,000 and 1,000,000, preferably between 100,000 and 500,000 daltons, in which case the criterion of solubility in the support component T must be satisfied. The BP binder is already used in solution in a suitable solvent, preferably in the support component T.

  The presence of the polymeric binder B-P is not absolute.

  ment necessary, but to harden, it needs at least one reactive binder system B-R. These systems can consist only of a reactive binder, for example an alkyd resin, such as for example that Alkydal (R)

  F26, or at least two constituents, which hardens

  feels in the prevailing conditions (cf. H. Wagner, H. F.

  Sarx, Lackkunstharze loc. cit .; Kirk-Othmer, Encyclope-

  dia of Chemical Technology, 3rd ed., vol. 6, p. 427-

445, J. Wiley 1979).

  The binders that can be used can be chosen from

  polycondensation resins, poly-

  addition and polymerization resins. The following groups may be cited as examples: - Alkyd resins, in particular modified with an oil, for example oxidized alkyd resins or

  alkyd resins with added diisocyanate, plas-

  chlorinated ticks, polystyrene, nitrocellulose, vinyl or epoxy resin, aminoplasts (plus an epoxy resin) or silicone, Epoxy resins modified by an oil and added with aminoplasts. The oil content can then be between 20 and 80% by weight, - Phenoplasts (with or without epoxy, vinyl acetals or aminoplasts components),

  - Vinyl acetals with or without allyl components -

  phenolic aminoplastics, - Polyester and triazine resins, Allyl polyesters, - Complex amino resins,

  - Indene and coumarone resins.

  Mention may be made, for example, of the BR binders, formed from, for example, an aromatic polyisocyanate (for example commercial products of the DESMODUR (R) type, products of Sté Bayer AG), and of polyesters or polyethers comprising groups free hydroxyls (for example commercial products of the DESMOPHEN (R) type from Sté Bayer AG), or else those which are prepared by the reaction of polyisocyanates with acrylic resins containing hydroxy groups (for example the commercial product JAGOTEX (R) F232, product of J ger Company,

Fabrik chemischer Rohstoffe).

  To have three-dimensional crosslinking, at least one of the substances participating in the reaction

  must contain in its molecule at least 3 reactive groups

  tifs. The varnishes L and optionally L ′ may also contain functionalized monomers such as (meth) acrylic acid, in order to improve the adhesion strength, in amounts of 0 to 50% by weight relative to the sum of the BP binders and BR, and furthermore monomers

  known per se (cf. Rauch-Puntigam, Acryl-und Methacryl-

  verbindungen, Springer-Verlag 1967), for example esters of (meth) acrylic acid and polyalcohols (polyols), such as glycol dimethacrylate, etc., usually in amounts less than 15% by weight. Examples of binders should be mentioned

  combinations of B-P binders, such as poly (metha-

  methyl crylate), possibly most often containing less than 15% by weight of a comonomer, for

  example methyl acrylate, 2- (meth) acrylate

  ethylhexyl, etc., and of a binder B-R, formed for example from an aromatic polyisocyanate (for example the

  commercial product DESMODUR (R) N 75) and a polyacry-

  late hydroxylated (commercial product JAGOTEX (R) F 232).

  We can indicate as indicative weight proportions

  ves a ratio of B-P to B-R of (3-1): 1.

  The liquid support constituent T located in the varnish L guarantees the spraying ability, to volatilize after a certain time (of drying), suitably chosen. The support component T therefore has to

  indicative boiling point (under the conditions

  normal conditions) from 50 to 220 and preferably from 75 to

170 C.

  (In fact, we can also arrive at the objective set, possibly using a combination of a

  constituent with high boiling point and a consti-

killing at low boiling point).

  The support component T can thus be advantageously

  sely chosen from the group comprising:

  - Monomers, in particular polymeric monomers

  sands by radical polymerization, for example those of the (meth) acrylate type, in particular comprising C1-C6 alkyl radicals, very particularly C1 or

C2 (= T-M).

  - Solvents, for example of the hydrocarbon type

  res (aromatic), ketones (= T-L).

  As additional criteria for choosing the support component T-L, it is possible to use an evaporation index (the ether having an index equal to 1) of 2 to

  and in particular from 2.5 to 50. The evapora-

  tion (vaporization index) is defined by time, based on ethyl oxide, at the end of which a certain quantity of a solvent evaporates (usually 0.3 ml,

  applied in 5 seconds on a filter paper at a dis-

  10 ni). (Cf. DIN 53 170; Ullmanns Encyclopâdie der Techn. Chemie, 4th ed., Vol. 16, p. 289, V.C.

1978).

  Mention may be made, as examples of the support component T-M, of methyl methacrylate, acrylate of

  methyl, ethyl methacrylate, n- methacrylate

  butyl, etc. Examples of the constituent can be cited

  support T-L butyl acetate, ethoxy aracetate-

  ethyl, etc., and hydrocarbons such as for example that

  Shellsol (R). You can get some interesting results-

  health with a combination of T-L and T-M.

  The amount of the support component T in the varnish L is generally between 40 and 90% by weight, the amount of the polymer binder B-P is between O and

  , preferably between 0.5 and 10 and very particular-

between 1 and 10% by weight.

  The amount of pearlescent pigment in the varnish L for

  before being sprayed is usually between 1 and

  and preferably between 2 and 15% by weight.

  A composition representative of varnish L can thus be presented below (approximate values): parts by weight of methyl methacrylate 5 parts by weight of PMMA parts by weight of a pearlescent pigment parts by weight of an alkyd resin, for example

Alkydal (R) F26.

  As solvents to formulate the pistol varnish

  lable, we use those already mentioned for the

  constituent T, for example butyl acetate, acetate

  ethyl tate and / or a monomer such as MMA and / or Shellsol (R) A. For example, the initiator initiating radical polymerization is transformed, in order to obtain a varnish which can be applied with a spray gun, with the formulation of varnish above, in a weight proportion of 1: 2, adding about 1 to 2 parts

  by weight per 100 parts by weight of sprayable varnish.

  To prepare the varnish L, we can for example proceed by dissolving all the constituents, with the exception of the binder BR, in the constituent support T using a stirrer with fins, then adding the Iriodin (R) and proceeding to an intense dispersion using the paddle stirrer. Then we add and we

dissolves the binder B-R.

  According to the current state of the art, and conform-

  In the present invention, the term "casting resins" means synthetic curable resins, liquids,

  can be poured into molds, the hardening of which

  This gives polymer molded objects. European patent N 218 866 and also in the publications US-A 4 786 660, 4 221 697 or 4 251 576 will find

  corresponding casting resins G, perfectly suited

  for the intended use, or corresponding prepolymers

  heavy. Preferably, the casting resins G appear

  stick to acrylic resins, and it's all about

  especially polymers based on methyl methacrylate, in which case a special use will be made

  mixture of a prepolymer and the monomers. Preferably

  rence, it is a "loaded" casting resin,

  containing fillers, and in particular heavily loaded casting resins, especially

  resins in which the fillers represent

  try 50 to 80% by weight of the casting resin.

  The finely divided organic or mineral substances used for the casting resins can be used as fillers F. It is preferable

  not to exceed a particle size of 100 μm. We pre-

  granular particles. Optionally, it may prove advantageous to remove, by heating to about 250 ° C., the moisture bound by absorption in the particles. The fillers F can be

  natural products, or produced by syn-

  thesis. Mechanical properties such as hardness,

  or the modulus of elasticity in shear, dependent

  tooth of the intended application of the casting resins. he

  it can then be interesting to adjust the elastic module-

  shear rate at least 5 GN.m-2. Mineral substances such as aluminum oxides, aluminum hydroxides and their derivatives, such as double metal oxides, may be used, for example.

  alkali and alkaline earth metals, and hydroxy-

  alkaline earth metals, clays, silica

  in its different forms, silicates, aluminum-

  silicates, carbonates, phosphates, sulfates, sulfides, oxides, coal, metals and metal alloys. Mention may also be made, as suitable examples, of synthetic substances such as glass powder, ceramics, porcelain,

  slag or finely divided synthetic SiO2.

  The different forms of the

  silica, such as quartz (quartz powder), tri-

  dymite and cristobalite, as well as kaolin, talc, mica, feldspar, apatite, barite, gypsum, chalk, limestone or dolomite. If necessary, mixtures of materials may also be used.

  charge. The amount of fillers in the resi-

  nes pouring is generally at least 20% by weight. In general, we do not exceed an amount of 80% by weight. As a guideline value, the filler content of the casting resins can be given 50 to% by weight. The fillers can be

  manufactured according to the different grain sizes required

  saires, by using known methods, for example

  by fragmentation and grinding. We prefer very special-

  cristobalite and aluminum hydroxide.

  The implementation of the method according to the invention pre-

  assumes that conventional molds and conventional spraying devices are used. The terms of

  the application can be advantageously highlighted

  dence on a metal plate, for example on a nickel-plated brass plate, polished until presenting a

  high gloss. The optimal temperature for surfa-

  these metals intended to receive the deposit, is 85 C. It is recommended to precede the operation with a heating of approximately 30 minutes, for example in

  drying oven at this temperature.

  The application can be done using an appropriate spray gun (for example of SATA brand

  Minijet), for example having a 0.8 mm nozzle and tra-

  brave under a pressure of 2.5 bar. Advantageously, the different varnish films are each prepared by double spraying the varnishes L ′ and L over the entire surface of the metal plate. The duration of lacquering is generally 2 to 2.5 minutes. Immediately after the last application, the object is again placed in a heating chamber (dry oven) at 85 C. In a short time, for example in less than 5 minutes, the resin is then advantageously introduced. Casting G. The procedure will be explained in more detail using a PMMA / MMA casting resin containing a filler. For example in about 3 minutes, and from the metal plate

  varnished, of a second metal plate not varnished cor-

  corresponding to the first (for example 350 x 350 x 4 mm) and a sealing bead (for example a PVC bead of 4 mm in diameter), a forming chamber is produced, into which the resin is introduced very loaded, possibly colored in the mass

  (degassed), in which the synthetic resin hardens

  ble is for example a mixture of PMMA and MMA, and

  comprising at least one initiator triggering the polymer

  radical cation, for example a perester such as bis- (4-tert-butylcyclohexyl) peroxydicarbonate, in usual amounts (for example from 0.5 to 5% by weight relative to the monomers), and this in a short time , for example in about 1.5 minutes. After sealing the forming chamber, an annealing is carried out first at high temperature - for example at around 65 ° C. and in a water bath, the forming chamber advantageously being in a horizontal position, with the varnished side facing towards

  the bottom -, and this for a time for example of 20 minutes

  and then at an even higher temperature, for example at 105 ° C., preferably in a dry oven for 15 minutes. Then the polymer molded object is extracted from the forming chamber at a temperature of about 60 to C. The process according to the invention makes it possible to obtain new polymer molded objects, constituted by casting resins and having a metallic surface effect. metallic shine, possibly colored and very uniform. Even after prolonged storage in water (test: 24 hours in hot water at 90 ° C), they show no surface color in white,

  called in English "Water-Whitening".

  The invention will be better understood with regard to the examples

  ples below and indications on the preparation

tion of polymeric molded objects.

Examples

  A) Preparation of the varnish with the spray gun L

Example 1:

  Is dissolved in 71 parts by weight of methyl methacrylate 5.0 parts by weight of a poly (methyl methacrylate) containing 10% by weight of methyl acrylate (average molecular mass by weight Mw = about 350,000). 1 part by weight of glycol dimethacrylate, 3 parts is added to this solution, before dissolution.

  by weight of Alkydal (R) F26 (60% in xylene, pro-

  produced by BAYER AG). With stirring using a paddle stirrer, 20 parts are added to this syrup.

  weight of Iriodin (R) 9111 Rutil Feinsatin WR (Merck Company).

  The agitation lasts 30 minutes. We add to 50 parts in

  weight of this varnish containing Iriodin, before disso-

  lution, 12.5 parts by weight of Shellsol (R) A (Shell Company), 12.5 parts by weight of n-butyl acetate and 1 part by weight of Interox (R) BCHCP = peroxydicarbonate

  bis- (4-tert-butylcyclohexyle), from the company Peroxid-

Chemie GmbH.

Example 2:

  We proceed as in Example 1, but we replace

  Iriodin (R) 9111 Rutil Feinsatin WR by the same quan-

  Iriodin (R) 9514 Silkrot WRII.

  B) Preparation of the varnish with a spray gun. It is dissolved in 75 parts by weight of methyl methacrylate 5.0 parts by weight of a poly (methyl methacrylate) containing 10% by weight of acrylate.

  methyl (Mw = about 350,000), and dispersed with Dis-

  dissolve for 15 minutes at around 10.0 m / s 45 parts by weight of silanized cristobalite (product SILBOND (R)

  6000 MST, from Quarswerke Frechen). We add to this

  pension, before dissolution, 1 part by weight of dimen-

  glycol thacrylate and 3 parts by weight of Alkydal (R)

  F26 (60% in xylene, product of BAYER AG).

  50 parts by weight of this varnish are added.

  holding cristobalite, before dissolution, 12.5 parts by weight of Shellsol (R) A (Shell Company), 12.5 parts by weight of n-butyl acetate and 1 part by weight

  Interox (R) BCHPC = bis- (4-tert-

  butylcyclohexyle), from Peroxid-Chemie GmbH.

* C) The loaded casting resin

  To a preliminary solution of a prepolymer, cons-

  consisting for example of 40 parts by weight of a solution of MMA and PMMA (weight proportions 35: 5), which

  still contains cross-linking agents and possibly-

  Lement a silane with a silanization catalyst, is added by dispersing 50 to 80 parts by weight of a

  mineral filler. Preferably, cristo lite or aluminum hydroxide is used. In addition to

  mold release such as stearic acid, coating resin

  the product also contains a polymerization initiator such as

  for example that bis- (4-tert-

  butylcyclohexyle), or a common redox system.

  D) Preparation of polymer molded articles The preparation of polymer molded articles is described in more detail above, in the relative paragraph.

to the implementation of the process.

  E) Control of the bleaching of molded objects with water

  From the cast plates, we cut proofs

50 x 50 mm vette.

  The test pieces are placed for 24 hours in water at 90 C. They are still stored for 24 hours at room temperature in air, then the

  test pieces to a sample as delivered.

  Results: The molded articles according to the invention show virtually no lightening after treatment with

  water, compared to samples as delivered. The hardened casting resins without coating with a pearlescent pigment5 show a clear lightening after the water whitening test (in English: "Water-Whitening").

Claims (13)

  1. Polymeric molded articles obtained from   highly loaded casting resins with over-   metallic glossy face, characterized in that the metallic glossy surface is a coating nant a pearly pigment.   2. Polymeric molded articles according to claim   1, characterized in that the metallic glossy surface   that is obtained with a colored pearly pigment.   3. Polymeric molded articles according to the claims   1 and 2, characterized in that the casting resin   contains PMMA / MMA as a hardened synthetic resin sand.   4. Process for preparing polymeric molded objects   res from highly loaded casting resins, present   both a metallic shiny surface, possibly   colored, characterized in that it is applied to an over-   face of the forming mold, before introduction of the casting resin, a curable coating of a varnish composition L containing a pearlescent pigment, then, after the drying of the varnish film, the casting resin is introduced into the mold, it is polymerizes on heating, then we unmold it.   5. Method according to claim 4, characterized in that, in a first lacquering step, one applies   L 'varnish without the addition of pearlescent pigment, but containing   filler, and after drying, apply the varnish L according to claim 4, introduce the   casting resin in the mold, it is polymerized by heating fage and finally we unmold.   6. Method according to claims 4 and 5, charac-   terized in that the varnish L also contains, in addition to the pearlescent pigment, a binder B and at least one liquid support constituent T.   7. Method according to claims 4 and 6, charac-   terized in that the binders B include, in addition to the system   hardenable B-R, a B-P polymer binder.   8. Method according to claim 7, characterized in that the polymeric binder B-P is a homopolymer or a copolymer of methyl methacrylate.   9. Method according to claims 4 and 6, charac-   terized in that the liquid support constituent T a,   under normal conditions a boiling point taken between 50 and 200 C.   10. Method according to claim 9, characterized in that the liquid support constituent T has, under normal conditions, a boiling point of 75 to C.   11. Method according to claims 4, as well as 9   and 10, characterized in that the support component T consists, in whole or in part, of monomers   polymerizable by radical polymerization.   12. Method according to claim 11, characterized in that the support component T consists, in whole or in part, of one or more alkyl esters   (meth) acrylic acid, with 1 to 6 carbon atoms bone in the alkyl fragment.   13. The method of claim 11, characterized in that the support component T is, in whole or   in part, consisting of methyl methacrylate.