HK1098429A - Laser-weldable plastic materials which are transparently, translucently or opaquely dyed by means of colorants - Google Patents

Description

Laser-weldable transparent, translucent or opaque plastics material coloured by a colouring agent

Technical Field

The invention relates to transparent, translucent or opaque plastic materials colored with colorants, wherein the plastic materials are laser-weldable due to the content of nanoscale laser-sensitive particles, and to a method for producing such plastic materials and to their use.

Background

The use of laser energy to weld plastic parts is well known per se. Laser weldability results from the absorption of laser energy in the plastic, either directly through interaction with the polymer or indirectly using a laser sensitive agent attached to the plastic. The laser sensitive agent may be an organic colorant or pigment that causes localized thermalization of the plastic through absorption of laser energy. In laser welding, the plastic material is heated strongly in the connecting region by absorption of laser energy so that the material melts and the two parts are welded to one another.

In practice, the principle of compound formation between the connection portions in laser welding is based on the fact that the connection portions facing the laser source have a transparency sufficient for the light of the laser source having a specific wavelength, so that the irradiation can reach the connection portions situated below, where the irradiation is absorbed. Due to this absorption, heat is released so that in the contact area of the connecting portion, not only the absorbing material but also the transparent material is locally melted and partially mixed, by which cooling a composite is formed. As a result of which the two parts are welded to one another in this manner.

Laser weldability is a function of the plastic and/or polymer properties on which it is based, the nature and content of all laser-sensitive additives, and the wavelength and radiation energy of the laser used. In addition to carbon dioxide and excimer lasers, Nd: YAG lasers (neodymium-doped yttrium-aluminum-garnet lasers) with typical wavelengths of 1064nm and 532nm are increasingly used in this technology, even diode lasers being used in recent years.

Laser-weldable plastics containing laser-sensitive additives in the form of colorants and/or pigments generally have a more or less pronounced coloring effect and/or opacity. In the case of laser welding, the moulding compounds used to prepare the laser absorbers are most often prepared by incorporating carbon black.

DE 10054859a1 describes a method for laser welding of plastic molded parts, in which a laser beam is guided through a laser-transparent molded part I and is caused to heat in a laser-absorbing molded part II, so that welding takes place. The molded parts contain laser-transparent and laser-absorbent colorants and pigments, in particular carbon black, which cooperate with one another in such a way that a homogeneous color undertone is produced. The material is naturally opaque. Since carbon black leads to strong black coloration even at low concentrations, only dark or grey shades are possible for the product. Furthermore, it is generally possible to weld transparent and/or laser transparent materials to opaque colored materials.

In principle, the laser-transparent connecting parts and the laser-absorbing connecting parts can be set to the same hue in accordance with the teaching of DE 10054859a 1. However, completely different colorants are necessary for this purpose. The person skilled in the art is advised to carry out the test in this case.

Such same color settings with different colorants typically have different aging behavior under environmental influence to cause different color changes in use and over time.

The connection of two transparent plastic components with a color arrangement white/white, the same color/the same color, in particular an unfavorable light arrangement, or a white or light arrangement by laser welding is only possible without satisfactory or difficult laser welding at all. There is therefore a need for plastics with the mentioned combinations of joining by laser welding.

Laser-weldable plastics having a precisely defined, freely selectable color of transparent, translucent and opaque colored, in particular those additionally resistant to natural ageing, are not known from the relevant art.

Disclosure of Invention

The invention is therefore based on the object of providing transparent, translucent or opaque laser-weldable plastics which are coloured with colorants, in particular those having a light hue. For this purpose, laser-sensitive additives for plastics are used which can be made laser-weldable without the transparency and/or the colour of the material being impaired.

Plastics containing laser sensitive additives that do not affect the inherent color of the plastic are described. This will apply to coloring and aging behavior. Plastics are basically provided with colorants and/or pigments which are laser-transparent per se to set the desired color and/or opacity. For the purpose of laser welding, laser-absorbing connecting parts made of such plastics contain laser-sensitive additives.

It has surprisingly been found that transparent, translucent or opaque laser-weldable plastics coloured with a colorant can be made laser-markable and/or laser-weldable plastics without the colour and/or transparency being impaired due to the presence of an amount of nano-scale laser-sensitive particulate filler.

The object of the present invention is therefore a laser weldable plastic which is transparent, translucent or opaque, coloured by a colouring agent, characterized in that it is laser weldable due to the presence of a certain amount of nano-scale laser-sensitive particles.

Furthermore, the object of the present invention is the use of nano-scale laser-sensitive particles for the manufacture of transparent, translucent or opaque laser-weldable plastics coloured with a colouring agent.

Furthermore, the object of the present invention is a process for the preparation of transparent, translucent or opaque laser-weldable plastics coloured by colorants by means of nanoscale laser-sensitive particles, the particles of which are mixed into the plastic matrix under high shear.

The present invention is based on the recognition that laser marking pigments known from the related art are unsuitable for use in high-transparency systems in terms of their particle size and their morphology, since they generally greatly exceed the critical dimension of one quarter of the wavelength of visible light of about 80 nm. Laser-sensitive pigments having particle sizes with primary particles below 80nm are well known, but these are not provided in the form of isolated primary particles or small aggregates, as is the case in carbon black, but are obtained, for example, only as highly aggregated, partially aggregated particles having a considerably larger particle diameter. The known laser marking pigments therefore cause considerable light scattering and thus a whitening of the plastic.

Furthermore, the present invention is based on the recognition that laser marking pigments known from the related art raise the turbidity of materials, spoil the color of materials and necessitate color correction due to their inherent color and their inadequate dispersibility, the color correction not being satisfactory and deviations from the desired color having to be accepted.

According to the invention, the nanoscale laser-sensitive particles are incorporated into plastics, in particular those which are transparent or translucent themselves and are additionally coloured, white or opaque, in order to make them laser-weldable.

Laser-sensitive nano-scale particle additives are understood to be all inorganic solids which are absorbers in the characteristic wavelength range of the laser light to be used and which are thus capable of generating local thermalization in the plastic matrix in which they are embedded, resulting in melting of the plastic, such as metal oxides, mixed metal oxides, composite oxides, metal sulfides, borides, phosphates, carbonates, sulfates, nitrides, etc. and/or mixtures of these compounds.

Nanoscale is understood to mean that the largest diameter of the discrete laser-sensitive particles is less than 1 μm, i.e. in the nanometer range. In this case, this size definition relates to all possible particle morphologies such as primary particles and possible aggregates and agglomerates.

The particle size of the laser sensitive particles is preferably 1-500 nm, especially 5-100 nm. If the particle size is chosen below 100nm, the metal oxide particles are no longer visible as such and do not impair the transparency of the plastic matrix.

The content of the laser-sensitive particles in the plastic is preferably 0.0001 to 0.1 wt%, more preferably 0.001 to 0.01 wt%, based on the plastic. In this concentration range, sufficient laser weldability of the plastic matrix is generally achieved for all plastics initially considered.

If the particle size and concentration are chosen appropriately within the given ranges, impairment of the intrinsic transparency can be avoided even for highly transparent matrix materials. Thus, a lower concentration range is selected for laser-sensitive pigments having a particle size above 100nm, and a higher concentration is preferred for particle sizes below 100nm as well.

Doped indium oxide, doped tin oxide, doped antimony oxide and lanthanum hexaboride are preferably initially considered as nanoscale laser-sensitive particles for producing transparent, translucent or opaque laser-weldable plastics colored with colorants.

Particularly suitable laser-sensitive additives are indium-tin oxide (ITO) or antimony-tin oxide (ATO) and doped indium-tin and/or antimony-tin oxides. Indium-tin oxide is particularly preferred and "blue" indium-tin oxide can in turn be obtained by partial reduction methods. The non-reduced "yellow" indium-tin oxide can lead to a visually perceptible slight yellow spot in the plastic at higher concentrations and/or at the upper particle size, while the "blue" indium-tin oxide does not cause any visible color change.

The laser-sensitive particles to be used in accordance with the invention are well known per se and are commercially available even in the form of nano-scale, i.e. as discrete particles having a size below 1 μm, in particular in the size range preferred here, usually in the form of a dispersion or in the form of agglomerates of readily redispersible, powdery nano-scale particles.

The laser-sensitive particles are usually provided as agglomerated particles, for example, as agglomerates whose particle size can be from 1 μm to several millimeters. These agglomerates can be mixed into a plastic matrix using the method according to the invention with a strong shearing action, wherein the agglomerates are broken up into primary particles of nanometric dimensions.

The degree of agglomeration was determined in accordance with DIN 53206 (8.1972).

Nanoscale particles, such as in particular metal oxides, can be produced, for example, by pyrogenic processes. Such a process is described, for example, in EP 1142830A, EP 1270511 a or DE 10311645. Furthermore, the nano-scale particles can also be prepared by precipitation methods, for example as described in DE 10022037.

Nanoscale laser-sensitive particles can be added to almost all plastic systems to provide their laser weldability. Plastics in which the plastic matrix is based on poly (meth) acrylates, polyamides, polyurethanes, polyolefins, styrene polymers and styrene copolymers, polycarbonates, silicones, polyimides, polysulfones, polyether sulfones, polyketones, polyether ketones, PEEK, polyphenylene sulfides, polyesters (e.g. PET, PEN, PBT), polyethylene oxides, polyurethanes, polyolefins or fluorine-containing polymers (e.g. PVDF, EFEP, PTFE) are customary. To compositions containing as components the above-mentioned plasticsOr into polymers derived from such polymers by subsequent reaction. These materials are well known and commercially available in a variety of forms. The advantages of the nano-scale particles according to the invention are due in particular to the fact that they contain coloured transparent or translucent plastic systems such as polycarbonates, transparent polyamides (e.g. Grilamid)^®TR55、TR90、Trogamid^®T5000, CX7323), polyethylene terephthalate, polysulfone, polyethersulfone, cycloolefin copolymer (Topas)^®、Zeonex^®) Polymethacrylates and their copolymers, since they do not affect the transparency of the material. Furthermore, transparent polystyrene and polypropylene and all partly crystalline plastics which can be processed into transparent films or mouldings by using nucleating agents or special processing conditions can be cited. In addition, the colored opaque plastic may be provided with nanoscale laser-sensitive pigments.

Polyamides are generally prepared from the following components: branched and unbranched aliphatic (6 to 14C atoms), alkyl-substituted or unsubstituted alicyclic (14 to 22C atoms), arylaliphatic diamines (C14 to C22), and aliphatic and alicyclic dicarboxylic acids (C6 to C44); the latter may be partially substituted by aromatic dicarboxylic acids. In particular, the transparent polyamide may additionally consist of monomer components having 6C atoms, 11C atoms and/or 12C atoms, which are derived from lactams or ω -aminocarboxylic acids.

Preferably, but not exclusively, the transparent polyamide according to the invention is prepared from the following components: glyceryl trilaurate lactam or omega-aminododecanoic acid, azelaic acid, sebacic acid, n-dodecanedioic acid, fatty acids (C18-C36; for example under the trade name Pripol^®) Cyclohexane dicarboxylic acids, these aliphatic acids being partially or totally substituted by iso-terephthalic acid, naphthalene dicarboxylic acid, tributyl isophthalic acid. Furthermore, decaalkanediamines, dodecanediamines, nonanediamines, hexamethylenediamines and the alkyl-substituted/unsubstituted cycloaliphatic diamines which are typically present in unbranched, branched and substituted form may also be usedRepresents bis- (4-aminocyclohexyl) -methane, bis- (3-methyl-4-aminocyclohexyl) -methane, bis- (4-aminocyclohexyl) -propane, bis- (aminocyclohexane), bis- (aminomethyl) -cyclohexane, isophorone diamine or even substituted pentamethyldiamines.

Examples of corresponding transparent polyamides are described, for example, in EP 0725100 and EP 0725101.

Colored transparent, translucent or opaque plastic systems based on polymethacrylates, bisphenol-a-polycarbonates, polyamides and cyclic olefin copolymers made from norbornene and alpha-olefins are particularly preferred, which can be made into laser-weldable plastics by means of the nanoscale particles according to the invention without impairing the color and transparency of the material.

The neutral intrinsic color of these nanoscale laser-sensitive additives is advantageous in pigmented transparent, translucent and opaque systems, since for plastics the choice of free color is made possible.

Those colorations which have only a slight intrinsic absorption, i.e. laser transparency, in the range of interest between 800 and 1500nm are considered to begin with.

In order to identify the colorant, the nomenclature of the color index (c.i.) is used below. All colorant names such as solvent orange or pigment red 101 are c.i. names (the name component c.i. is omitted from table 1 below for simplicity).

Table 1: laser-transparent colorants

Colorant c.i.	Preferred concentration is% by weight	Particularly preferred concentrations are% by weight
			Pigment orange 64	0.01-0.5	0.015-0.05
Solvent orange 60	0.01-1.0	0.01-0.5
			Solvent orange 106	0.01-1.0	0.01-0.5
Solvent orange 111	0.01-1.0	0.01-0.5
			Pigment Red 48	0.05-1.0	0.05-0.5
Pigment Red 101	0.005-0.5	0.01-0.3
			Pigment Red 144	0.005-0.5	0.01-0.2
Pigment Red 166	0.005-0.5	0.01-0.2
			Pigment Red 178	0.01-1.0	0.03-0.5
Pigment Red 254	0.01-1.0	0.03-0.5
			Solvent Red 52	0.01-1.0	0.01-0.5
Solvent Red 111	0.01-1.0	0.01-0.5
			Solvent Red 135	0.01-1.0	0.01-0.5
Solvent Red 179	0.01-1.0	0.01-0.5
			Pigment green 7	0.0005-1.0	0.0005-0.5

Pigment Green 17	0.01-1.0	0.03-0.5
			Pigment Green 50	0.005-0.5	0.005-0.05
Solvent green 3	0.01-1.0	0.01-0.5
			Solvent Green 20	0.01-1.0	0.01-0.5
Pigment blue 15	0.005-1.0	0.01-0.5
			Pigment blue 29	0.02-5.0	0.2-2.0
Pigment blue 36	0.015-0.5	0.015-0.25
			Pigment yellow 93	0.1-1.0	0.1-0.5
Pigment yellow 110	0.01-1.0	0.03-0.5
			Pigment yellow 150	0.0005-0.5	0.0005-0.25
Pigment yellow 180	0.01-1.0	0.03-0.5
			Pigment yellow 184	0.005-0.5	0.005-0.25
Solvent yellow 21	0.005-0.5	0.005-0.5
			Solvent yellow 93	0.005-1.0	0.005-0.5
Pigment brown 24	0.005-0.5	0.005-0.15
			Pigment Violet 19	0.01-1.0	0.030.5
Pigment Violet 13	0.01-1.0	0.01-0.5
			Pigment Violet 46	0.01-1.0	0.01-0.5

Some of the colorants cited may be present in different structures that are slightly different from each other. For example, pigments may be colored with different metal ions, whereby different forms of pigments occur. This form is identified according to c.i. by adding suffix colons and numbers, for example for pigment red 48 with sodium, pigment red 48:1 with calcium, pigment red 48:2 with barium, pigment red 48:3 with strontium and pigment red 48:4 with magnesium. The c.i. colorant names referred to herein are understood in such a way that they include all forms and/or structures. They are all reported in the color index.

The laser-weldable plastics according to the invention are usually provided as molded bodies or semi-finished products. Laser weldable lacquers are also possible.

The preparation of the highly transparent laser-weldable plastics according to the invention is carried out in a manner known per se in accordance with processes and methods which are well known and customary in the manufacture and processing of plastics. In this case, the laser-sensitive additives can be introduced into the individual reactants or reaction mixtures before or during the polymerization or polycondensation or even mixed during the reaction, using the specific production methods of the corresponding plastics known to the person skilled in the art. In the case of polycondensates, such as polyamides, for example, additives may be added to one of the monomers of the monomer component. This monomer component can then be subjected to polycondensation in the usual manner together with the remaining reactants. Furthermore, after the formation of the macromolecules, the resulting high molecular weight intermediate or end products can also be mixed with laser-sensitive additives, in which case all methods known to the person skilled in the art can likewise be used.

In the customary apparatus and devices for this purpose, such as reactors, stirred tanks, mixers, roll mills, extruders and the like, fluid, semifluid and solid formulation components or monomers and, if necessary, additives, such as polymerization initiators, stabilizers (e.g.UV absorbers, heat stabilizers), visual brighteners, antistatics, softeners, mold release agents, lubricants, dispersants, antistatics, including also fillers and reinforcing agents or impact modifiers, are mixed and homogenized, if appropriate shaped, and then cured, depending on the compounding composition of the plastic base material. For this purpose, nanoscale laser-sensitive particles are added to the material at appropriate times and mixed homogeneously. The mixing of the nanoscale laser-sensitive particles in the form of a concentrated premix (masterbatch) with the same or a compatible plastic is particularly preferred.

It is preferred if the mixing of the nano-scale laser-sensitive particles into the plastic matrix is carried out under high shear in the plastic matrix. This can be done by appropriate setting of the stirrer, roll mill and extruder. In this way, any possible agglomeration or aggregation of the nano-scale particles into larger pieces can be effectively prevented; all large particles present were broken up. The corresponding process and specific process parameters selected are well known to those skilled in the art.

The plastic mouldings and semifinished products can be obtained from the monomers and/or prepolymers by injection moulding or extrusion from moulding compounds or by casting processes.

The polymerization can be carried out by methods well known to those skilled in the art, for example, by adding one or more polymerization initiators and initiating the polymerization by heating or irradiation. In order to obtain complete conversion of the monomers, the polymerization may be followed by a tempering step.

Laser-weldable lacquers are obtained by dispersing laser-sensitive oxides in customary lacquer formulations, brushing and drying or hardening the lacquer layer.

Suitable paint sets include, for example, powder paints, physically drying paints, radiation-curable paints, one-component or multi-component reaction paints such as two-component polyurethane paints.

After plastic moldings or lacquers are produced from plastics containing nanoscale laser-sensitive particulate solids, they can be welded by irradiation using a laser.

Laser welding can be performed on commercially available laser marking equipment, such as that manufactured by Baasel, having an output of 0.1 to 22 amperes and a mass of 1 to 100mms^-1StarMarkSMM65 type laser at forward speed. When setting the laser energy and the forward speed, it should be ensured that the output is not chosen too high and the forward speed is not chosen too low in order to avoid undesirable carbonization. At too low an output and too high an advancing speed, welding may be insufficient. The settings necessary in individual cases can also be determined for this purpose without any further influence.

For welding plastic molded bodies or plastic semi-finished products, it is necessary that at least one of the parts to be joined comprises the plastic according to the invention at least in the surface region, the joining surface being irradiated with a laser that is sensitive to particles contained in the plastic. This method is suitably performed so that the connecting portion facing the laser beam does not absorb the laser energy, and the second connecting portion is made of the plastic according to the invention, which portion is strongly thermalized at the phase boundary so that the two portions are welded to each other. A certain contact pressure is necessary to obtain a bond of the materials.

Detailed Description

Example 1:

preparation of colored transparent, colored translucent or opaque colored laser-sensitive mouldings

A colored transparent, colored translucent or opaque pigmented plastic molding compound containing a laser-sensitive nanoscale pigment is melted in an extruder and injected into an injection mold to form a plastic molded body in the form of a sheet or extruded to form a flat sheet, film or tube.

The mixing of the laser-sensitive pigment into the plastic molding compound is carried out under strong shear in order to break up the agglomerated particles that may be present into primary particles of nanometric dimensions.

Laser absorption: (^a) Preparation of the Molding Compound:

embodiment A^a

Trogamid, a commercial product of Marl, a high-performance polymer division of Degussa AG^®CX7323 as a plastic molding compound was compounded and granulated with nanoscale indium-tin oxide Nano ® ITO IT-05C5000 as a laser-sensitive pigment produced by Nanogate corporation at a concentration of 0.01% by weight and C.I. pigment Red 166(Scarlett RN, produced by Ciba Spezialit Ptenchemie) as a laser transparent colorant at a concentration of 0.01% by weight in a Berstorff ZE 2533D extruder at 300 ℃.

Embodiment B^a

The commercial product Vestamid L1901 from Marl, high-performance polymers department, from Degussa AG, was used as a plastic molding compound, compounded and granulated at 260 ℃ in a Bersfff ZE 2533D extruder with a nanoscale indium-tin oxide Nano ® ITO IT-05C5000 as laser-sensitive pigment from Nanogate at a concentration of 0.01% by weight and a C.I. pigment Red 166(Scarlett RN, from Ciba Spezialitatenchemie) as laser-transparent colorant at a concentration of 0.01% by weight.

Embodiment C^a

The commercial product Vestamid L1901 from Marl, high-performance polymers sector, from Degussa AG, was used as a plastic molding compound, compounded and granulated at 260 ℃ in a BerstorffZE 2533D extruder with a nanoscale indium-tin oxide Nano ® ITO IT-05C5000 as laser-sensitive pigment from Nanogate at a concentration of 0.01% by weight and C.I. pigment Green 7(Irgalite Green P, from Ciba SpezialFNit Tenchemie) as laser-transparent colorant at a concentration of 0.01% by weight.

Embodiment D^a

As plastic molding compound, the commercial product Plexiglas ® 7N from Degussa AG methacrylate division Darmstadt was used. Nanoscale indium-tin oxide Nano ® ITOIT-05C 5000 as a laser-sensitive pigment, produced by Nanogate, at a concentration of 0.01% by weight, and C.I. pigment Red 166(Scarlett RN, produced by Ciba Spezialit totenichemie) as a laser-transparent colorant, were compounded and granulated at 250 ℃ in a Berstorff ZE 2533D extruder. In the case of extrusion, preference may also be given to using high molecular weight molding compounds of the Plexiglas ® 7H type.

Embodiment E^a

As plastic molding compound, the commercial product Plexiglas ® 7N from Degussa AG methacrylate division Darmstadt was used. Nanoscale indium-tin oxide Nano ® ITOIT-05C 5000 as a laser-sensitive pigment, produced by Nanogate, at a concentration of 0.01% by weight, and C.I. pigment blue 29 (ultramarine blue), as a laser-transparent colorant, at a concentration of 0.01% by weight, were compounded and granulated in a BerstorffZE 2533D extruder at 250 ℃. In the case of extrusion, preference may also be given to using high molecular weight molding compounds of the Plexiglas ® 7H type.

Embodiment F^a

As plastic molding compound, the commercial product Plexiglas ® 7N from Degussa AG methacrylate division Darmstadt was used. Nanoscale indium-tin oxide Nano ® ITOIT-05C 5000 as a laser-sensitive pigment produced by Nanogate corporation at a concentration of 0.01% by weight and C.I. pigment Green 7(Irgalite Green FNP, produced by Ciba Spezialit Halite Tenchemie) as a laser-transparent colorant were compounded and granulated in a Berstorff ZE 2533D extruder at 250 ℃. In the case of extrusion, preference may also be given to using high molecular weight molding compounds of the Plexiglas ® 7H type.

Corresponding laser transparency: (^t) Molding compound A^t～F^tAccording to the above embodiment A^a～F^aBut with the difference that no laser sensitive pigment is added.

Example 2:

coloured transparent, coloured translucent or opaque coloured laser-sensitive casting

Preparation of PMMA semi-finished product

A0.01% by weight concentration of Nano-sized indium-tin oxide Nano ® ITO IT-05C5000 as a laser-sensitive pigment manufactured by Nanogate corporation was dispersed in 1000 parts of a PMMA/MMA prepolymer solution having a viscosity of 1000cP at a concentration of 0.001% by weight together with a dispersing agent and a coloring agent. After addition of 1 part of AIBN, the mixture was poured into a tank and polymerized in a water bath at 50 ℃ for 2.5 hours. The residual monomers were converted by subsequent tempering in a drying oven at 115 ℃. Thereby obtaining a laser absorbing semi-finished product.

To prepare a laser-transparent semifinished product, batches were prepared which did not contain laser-sensitive pigments.

If transparent semifinished products are to be produced, the soluble colorants in the tables (name "solvents") are preferably used. Weakly scattering micronized colorant pigments, such as ultramarine blue, can be used in nearly transparent settings. More strongly scattering pigments are suitable for translucent or opaque variants. The dispensing of colorants is well known to those skilled in the art. Examples and details relating to the polymerization are described in particular in DE 4313924.

Variant A

C.i. pigment red 166(Scarlett RN, manufactured by ciba spezialit petachemie) was used as a laser transparent colorant at a concentration of 0.01 wt%.

Variant B

C.i. pigment blue 29 (ultramarine blue, produced by ciba spezialit petienchemie) was used as a laser transparent colorant at a concentration of 0.01 wt%.

Modification C

C.i. pigment Green 7(Irgalite Green GFNP, produced by ciba spezialit santenchemie) was used as a laser transparent colorant at a concentration of 0.01 wt%.

Example 3:

performing laser welding

(cast PMMA with 0.01% by weight ITO content)

A colored transparent, colored translucent or opaque colored laser-sensitive plastic plate (size 60mm 2mm) made of cast PMMA with an ITO content of 0.01% by weight is brought into contact with the surface to be welded of a second colored transparent, colored translucent or colored opaque but laser-transparent plastic plate made of undoped cast PMMA. The plates were placed into the frit holders of a Starmark laser SMM65, manufactured by Baasel-Lasertechnik, in such a way that the undoped plates were placed on top, i.e. the undoped plates were first penetrated by the laser beam. The focal point of the laser beam is set to the contact surface of the two plates. The control unit of the laser is provided with a parameter frequency (2250Hz), a lamp current (22.0A) and a forward speed (30 mms)^-1). At the input the size of the area to be welded (22 x 4 mm)²) After that, the laser is started. At the end of the welding process, the welded plastic panels may be removed from the apparatus.

Adhesion values of 4 grades were obtained using a hand tear test.

Adhesion was evaluated as follows:

0 had no adhesion.

1 slight adhesion.

2 some adhesion; the separation is somewhat difficult.

3, good adhesion; separation is only possible in difficult situations and perhaps with the aid of tools.

4 inseparable adhesion; separation is only possible by cohesive failure.

Embodiment A

Molding compound A^aWith molding compound A^t

Standard of molding compound A^aThe resulting injection molded plastic plate (size 60mm by 2mm) was mated with a second standard molded compound A^tThe resulting injection molded plastic panels (60 mm by 2mm in size) were in contact. The panels were placed in a welded holder of a Starmark laser SMM65, manufactured by Baasel-Lasertechnik, Inc. in such a way that the panels were made of the moulding compound A^tThe finished plate is placed on top, i.e. from the moulding compound A^tThe finished plate is first penetrated by a laser beam. The control unit of the laser is provided with a parameter frequency (2250Hz), a lamp current (22.0A) and a forward speed (10 mms)^-1). At the input the size of the area to be welded (22 x 4 mm)²) After that, the laser is started. At the end of the welding process, the welded plastic panels may be removed from the apparatus.

Adhesion values of 4 grades were obtained using a hand tear test.

Variant a 1:

pigment blue 29 (ultramarine blue) is used as a colorant in plastics. Adhesion values of 4 grades were obtained using a hand tear test.

Variant a 2:

solvent orange 60 was used as a colorant in plastics. Adhesion values of 4 grades were obtained using a hand tear test.

Embodiment B

Moulding compound B^aWith a molding compound B^t

Standard of molding compound B^aThe resulting injection molded plastic panel (size 60mm by 2mm) was combined with a second standard molded compound B^tThe resulting injection molded plastic panels (60 mm by 2mm in size) were in contact. The plate was placed in such a way on the Baasel-Lasertechnik companyWelded seating of the produced Starmark laser SMM65 so that the molding compound B^tThe finished plate is placed on top, i.e. from the moulding compound B^tThe finished plate is first penetrated by a laser beam. The control unit of the laser is provided with a parameter frequency (2250Hz), a lamp current (22.0A) and a forward speed (10 mms)^-1). At the input the size of the area to be welded (22 x 4 mm)²) After that, the laser is started. At the end of the welding process, the welded plastic panels may be removed from the apparatus.

Adhesion values of 4 grades were obtained using a hand tear test.

Embodiment C

Molding compound C^aAnd molding compound C^t

Standard of molding compound C^aThe resulting injection molded plastic panel (size 60mm by 2mm) was combined with a second standard molded compound C^tThe resulting injection molded plastic panels (60 mm by 2mm in size) were in contact. The panels were placed in a welded holder of a Starmark laser SMM65, manufactured by Baasel-Lasertechnik, Inc. in such a way that the panels were made of the molding compound C^tThe finished plate is placed on top, i.e. from the moulding compound C^tThe finished plate is first penetrated by a laser beam. The control unit of the laser is provided with a parameter frequency (2250Hz), a lamp current (22.0A) and a forward speed (10 mms)^-1). At the input the size of the area to be welded (22 x 4 mm)²) After that, the laser is started. At the end of the welding process, the welded plastic panels may be removed from the apparatus.

Adhesion values of 4 grades were obtained using a hand tear test.

Embodiment D

Molding compounds D^aAnd molding compounds D^t

Standard of molding compound D^aThe resulting injection molded plastic panel (size 60mm by 2mm) was combined with a second standard molded compound D^tThe injection mold is madePlastic plates (size 60mm by 2mm) were contacted. The panels were placed in a welded holder of a Starmark laser SMM65, manufactured by Baasel-Lasertechnik, Inc. in such a way that the panels were made of the molding compound D^tThe finished plate is placed on top, i.e. from the moulding compound D^tThe finished plate is first penetrated by a laser beam. The control unit of the laser is provided with a parameter frequency (2250Hz), a lamp current (22.0A) and a forward speed (10 mms)^-1). At the input the size of the area to be welded (22 x 4 mm)²) After that, the laser is started. At the end of the welding process, the welded plastic panels may be removed from the apparatus.

Adhesion values of 4 grades were obtained using a hand tear test.

Embodiment E

Molding Compound E^aWith molding compound E^t

Welding similar to molding Compound D^aAnd molding compounds D^tAnd welding of (3).

Adhesion values of 4 grades were obtained using a hand tear test.

Embodiment F

Molding compounds D^aAnd molding compounds D^t

Welding similar to molding Compound D^aAnd molding compounds D^tAnd welding of (3).

[d1] Adhesion values of 4 grades were obtained using a hand tear test.

Claims (17)

1. A transparent, translucent or opaque plastic material coloured by a colouring agent, characterized in that: due to the content of the nano-scale laser-sensitive particles, they are laser-weldable.

2. A plastic material according to claim 1, characterized in that: the particle size of the laser sensitive particles is 1-500 nm.

3. A plastic material according to claim 1 or 2, characterized in that: the particle size of the laser sensitive particles is 5-100 nm.

4. A plastics material according to any one of claims 1 to 3 wherein: the content of the laser sensitive particles is 0.0001-0.1 wt% relative to the plastic material, and preferably 0.001-0.01 wt%.

5. A plastics material according to any one of claims 1 to 4 wherein: which comprises metal oxides, mixed metal oxides, composite oxides, metal sulfides, borides, phosphates, carbonates, sulfates, nitrides and the like and/or mixtures of these compounds as nanoscale laser-sensitive particles.

6. A plastics material according to any one of claims 1 to 5 wherein: which comprises doped indium oxide, doped tin oxide, doped antimony oxide, indium-zinc oxide or lanthanum hexaboride as nanoscale laser-sensitive particles.

7. A plastic material according to claim 6, characterized in that: which comprises indium-tin oxide or antimony-tin oxide as the nano-scale laser-sensitive particles.

8. A plastic material according to claim 7, characterized in that: which comprises blue indium-tin oxide as the nano-scale laser-sensitive particles.

9. A plastics material according to any one of claims 1 to 8 wherein: the plastic matrix is based on poly (meth) acrylates, polyamides, polyurethanes, polyolefins, styrene polymers and styrene copolymers, polycarbonates, silicones, polyimides, polysulfones, polyethersulfones, polyketones, polyetherketones, polyphenylene sulfides, polyesters, polyethylene oxides, polyurethanes, polyolefins, cyclic olefin copolymers or polymers containing fluorine.

10. A plastic material according to claim 9, characterized in that: based on polymethyl methacrylate.

11. A plastic material according to claim 9, characterized in that: based on bisphenol a polycarbonate.

12. A plastic material according to claim 9, characterized in that: which is based on polyamide.

13. A plastics material according to any one of claims 1 to 12 wherein: it is provided as a molded body, a semi-finished product or a painted product.

14. Use of nano-scale laser-sensitive particles for the preparation of a transparent, translucent or opaque laser-weldable plastic material coloured by a colorant.

15. A process for the preparation of a transparent, translucent or opaque laser-weldable plastic material according to one of claims 1 to 13, coloured with a colouring agent, characterized in that: the nano-scale laser-sensitive particles are mixed under high shear into a plastic matrix or a flowing monomer-containing casting formulation.

16. The method according to claim 15, characterized in that: the nano-scale laser-sensitive particles are mixed with the plastic material in the form of a concentrated premix into a plastic matrix or a flowing monomer-containing casting formulation.

17. Method for welding plastic mouldings or plastic semifinished products, at least one component to be joined comprising a plastic material according to one of claims 1 to 13 at least in the surface region of a joint region which is irradiated with a laser which is sensitive to particles contained in the plastic material.