HK1110555B - Moulded mass for producing objects that are poorly inflammable, pigment therefor, and use of the same - Google Patents

Description

Moulding material for producing highly flame-resistant articles, pigment for said material and use thereof

Technical Field

The present invention relates to molding materials for producing articles of high flame resistance, pigments for the same and their use.

Background

It is known to add flame-resistant materials to plastics in the form of fine particles and to disperse these fine particles throughout the plastics or in the surface region of the plastics. For example, german patent specification DE-a-10145093 describes polyphosphates of organic nitrogen bases (guanidine and melamine or melamine derivatives) as flame protection agents (flame retardants) in plastics and as flame retardants in textiles. International patent WO-A-00/02869 describes polyphosphates, especially in polyamides and polyesters of glass fibers, as flame protection agents. Other organic nitrogen bases are mentioned as fire protection agents in many other publications, and the trend in the industry is to use halogen-free fire protection agents, such as aluminum hydroxide, magnesium hydroxide or melamine cyanurate for this purpose.

When such flameproof protective agents are distributed in halogen-free thermoplastics, the adverse effect may occur, namely a change in the properties of the plastic in an undesirable manner.

In many fields of application, it is desirable to produce plastic articles which are flame-resistant and which can be written or marked by means of laser light, but in practice there is a problem in that halogen-free flame protection agents are not sufficiently contrasting (concentrate) and are therefore not of practical use.

Disclosure of Invention

It is an object of the present invention to provide a plastic molding material which ensures that the plastic article is laser writable and does not substantially adversely affect the properties of the plastic. The moulding materials of the invention for producing highly flame-resistant articles comprise a matrix formed from a thermoplastic and a particulate flame-retardant pigment dispersed in the matrix, which moulding materials are distinguished in that the pigment changes colour under the influence of a laser or the colour of the plastic matrix, and in that the pigment is the reaction product of at least one halogen-free flame-retardant organic nitrogen base and a salt or salt mixture which is reactive with the organic nitrogen base.

Any known thermoplastic can be used as matrix material, for example, the thermoplastic described by Ullmann's Encyclopedia of Chemistry, volume 15, page 457, which has been used for laser marking, optionally reinforced with glass fibers. Examples of suitable plastics are polyethylene, polypropylene, polyamides, polyesters, polyphenylene ethers, polyacetals, polybutylene terephthalate, polymethacrylates, polyoxymethylene, polyvinyl acetal, polystyrene, polyacrylic acid-butadiene-styrene (ABS), polyacrylonitrile-styrene-acrylate (ASA), polycarbonate, polyethersulfone, polyetherketones such as polyethyletherketone, polyvinyl chloride and thermoplastic polyurethanes.

Preferred polyesters are thermoplastic polymers having recurring ester groups in the main chain. Examples are polycondensation products of naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid (sebasic acid), dodecanedioic acid and cyclohexanedicarboxylic acids with diols, such as ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 4-butenediol or 1, 6-hexanediol, 1, 4-cyclohexanediol, 1, 4-bis- (hydroxymethyl) -cyclohexane, bisphenol A, neopentyl glycol, oligo-or polyethylene glycols, oligo-or polypropylene glycols, oligo-or poly (tetramethylene) glycols, mixtures of said diols and ester-forming derivatives thereof. Particularly preferred matrix components are polyethylene terephthalate, polybutylene terephthalate and polyether-ester block copolymers.

Polyamides which come into consideration are thermoplastic polymers having recurring amide groups in the main chain, homopolymers and copolymers with further comonomer groups.

Examples are polyhexamethylene adipamide, polyhexamethylene azelamide, polyhexamethylene sebacamide, polyhexamethylene dodecanediamide, poly-11-aminoundecanamide and bis- (p-amino-cyclohexyl) -methanedodecanoamide or the products obtained by ring opening of lactams, for example polycaprolactam or polylaurolactam. In addition, polyamides based on terephthalic acid or isophthalic acid as the acid component and/or trimethylhexamethylenediamine or bis- (p-amino-cyclohexyl) -propane as the diamine component and polyamide resins obtained by copolymerizing two or more of the above polymers or their components are suitable.

The thermoplastic polymer used as mixing partner (mixing partner) can be any other partially crystalline, liquid crystalline or amorphous polymer.

Polyurethane is particularly suitable because of its excellent mechanical properties and low processing cost. Thermoplastic polyurethanes are well known from a number of literature publications and patents.

Very surprisingly, the composition of the salt has a great improvement in contrast with respect to laser writability or markability and at the same time is improved in terms of fire protection.

The above-mentioned effects of the invention can be achieved by virtue of the pigments which on the one hand have flame-retardant properties and on the other hand produce laser-writability by absorption of laser light. The pigment is the reaction product of at least one halogen-free flame retardant organic nitrogen base and an active salt or salt mixture that is reactive with the nitrogen base. The organic nitrogen base is preferably melamine or a melamine derivative, such as melamine cyanurate, melamine orthophosphate, di-melamine orthophosphate, melamine pyrophosphate, melamine polyphosphate, melamine borate, melamine salts of phosphoric acid partial esters, one or more salts of phosphorus oxygen compounds (phosphorus oxygen compounds), ammonium polyphosphate, boron phosphate and mixtures thereof with synergists. The flame retardants used can be used in synergists selected from pentaerythritol, dipentaerythritol, THEIC, triazine polymers, melem, melam, urea, guanidine or phosphonate.

The term "salt" as used herein refers to a compound that at least partially dissociates in water into a cation and a cation or contains an acid residue and a base residue.

The term "color change" refers to a transition from one hue to another, such as from yellow to red, or from transparent to black. In this context, the term also denotes a change in lightness, for example from light brown to dark brown or a change in color of the plastic matrix.

The term "particulate" is intended to indicate that the pigment is in the form of fine solid particles, the quantitative parameter in this connection relating to the mean particle size (d) of the primary particles₅₀) And particle size. The primary particles have a particle size in the nanometer to micrometer range. Suitable average particle diameter (d) of the primary particles₅₀) Less than 10 microns, preferably less than 5 microns.

It is within the scope of the invention for the pigments of the invention to also contain other cations, in particular those of the elements of periods 2 to 5 of group I. Additional inorganic oxides and/or additional color-producing additives and/or additives that improve certain conventional properties, such as UV stabilizers, stabilizers against weathering, thermal and thermo-oxidative attack, to improve hydrolysis and nitrogen hydrolysis resistance, lubricants, mold release aids, nucleating agents, fillers, softeners and other additives may also be added to the pigment.

The elements are generally selected such that they have as strong an absorption as possible in the laser wavelength range used.

There is substantially no limitation on the wavelength range of the laser used. Suitable laser wavelengths are typically in the range of 157 nanometers and 10.6 microns. For example CO₂Lasers (10.6 microns) and Nd: YAG lasers (1064 nm) or pulsed UV lasers.

Typical excimer lasers have the following wavelengths: f₂Excimer laser (157 nm), ArF excimer laser (193 nm), XeCl excimer laser (308 nm), XeF excimer laser (351 nm), multiple frequency Nd: YAG laser with wavelength of 532 nm (frequency doubled), 355 nm (frequency tripled) or 265 nm (frequency quadrupled). Particularly preferred are Nd: YAG lasers (1064 or 532 nm) and CO₂A laser. Laser used in the inventionThe energy density of (A) is generally 0.3mJ/cm²To 50J/cm²In the range of (1), preferably 0.3mJ/cm²To 10J/cm²Within the range of (1). When a pulsed laser is used, the pulse frequency is generally in the range of 1-30 kHz.

In the present description, the term "pigment" refers to an organic or inorganic salt-type compound or a mixture of such salt-type compounds that undergoes a color change in an irradiated region under the influence of a laser source.

These compounds may be conventional salts with a stoichiometric ratio of one or more anions to cations derived from different elements, but may also be compounds in non-stoichiometric ratios. Anions of organic carboxylic acids and carbonic acid are preferred.

Any anion may be used, but anions of organic carboxylic acids and oxo-and/or carbonate anions other than phosphinates, diphosphinates and/or their polymers are preferred.

Preferred combinations are those in which the non-irradiated compound absorbs in the region of the wavelength of light used.

More preferred combinations are those in which the self colour (self colour) of those non-irradiated compounds can be adjusted by varying the molar ratio of the cations.

In a preferred embodiment of the invention, the non-irradiated compound has the highest possible lightness and as little self colour as possible. In this case, the irradiated compound should have as low a lightness as possible and as low a self-color as possible.

In another preferred embodiment of the invention, the non-irradiated compound has as high a lightness as possible and as low a color as possible; on the other hand, the irradiated component should have the clearest possible self-color.

In a preferred embodiment of the composition of the invention, the anions of the above-mentioned componentsIs of the general formula A_aO_o(OH)_y ^z-Wherein A is trivalent or pentavalent phosphorus, tetravalent molybdenum or hexavalent tungsten,

a, o and z independently represent integer values of 1-20, and

y is an integer between 0 and 10.

In another preferred embodiment of the composition of the invention, the pigment has at least one combination of two different elements selected from the group consisting of copper, tin, antimony and iron.

In a further preferred embodiment of the composition according to the invention, the pigment contains anions of phosphorus (V) and/or phosphorus (III) acids, their condensation products or, if appropriate, condensation products with further hydroxide anions, and Cu and Fe, Cu and Sn, Cu and Sb, or Sn and Fe as cations.

Preferably, metal salts are used which have a particularly high thermal stability so that no degradation occurs when they are doped into a polymer to produce a combination product. Salts or ligands with a thermal stability greater than 200 ℃ (2 wt% loss) are used, preferably with a stability greater than 250 ℃ (2 wt% loss), more preferably with a stability greater than 300 ℃ (2 wt% loss).

The photosensitive fire retardant composition is obtained by doping, reacting and mixing an organic nitrogen base with a metal compound. The term "blending" refers to the production of a mixture of one or more of the solid components in the powder state and the mixing of one or more of the solid components in a dissolved or suspended state followed by drying of the powdered product.

The products of the invention have flame retardancy and laser writability.

The invention also relates to pigments for producing articles which are both flame-retardant and laser-writable and which have the features of the molding materials described above. The invention also relates to the use of pigments having the characteristics given above for producing plastic articles which are both flame-retardant and laser-writable, in particular from thermoplastics.

Detailed Description

Example 1

The pigments used in the molding materials of the invention were produced as follows:

copper hydroxide (0.1 mole) and isocyanuric acid (0.1 mole) were placed in a mixer with water and stirred. Thus, a neutralization reaction takes place to form a salt. After 30 minutes, melamine (10 moles) and cyanuric acid (10 moles) were added in a precise ratio of 1: 1. The entire mixture was stirred for 1 hour and then dried under vacuum at 110 ℃.

The above components are used to obtain pigments with which the molding materials of the invention are obtained. The flame resistance and the laser writability of the molding materials were determined.

The laser was a commercially available Nd-YAG laser (wavelength 1064 nm). The contrast values were determined using a digital camera mounted on a microscope and image evaluation software. Flame resistance was measured using a UL Box according to UL 94. The CTI values were determined according to the standard DIN IEC 60112/VDE 0303 part 1, RAL 7035.

Polyamide 6, 6/6 (molar ratio 1: 1) 88% by weight

Melamine cyanurate (prepared as above) 12% by weight

UL94 VO

Contrast (K value) 4.2

CTI 520

The thermoplastic molding materials obtained are distinguished in both respects: excellent flame resistance (self-extinguishing) and high contrast values (K-value) in laser writing.

Example 2

The pigments used in the molding materials of the invention were produced as follows:

a50 liter reactor with a stirrer was charged with 29.25 liters of pure water. Orthophosphoric acid (74.75 moles) was added at room temperature with stirring. Since the reaction was exothermic, the temperature of the contents of the reactor rose and was held at 50 ℃ for 10 minutes. Subsequently, melamine (74.75 moles) was added slowly with stirring, avoiding blocking (crumbping). After a homogeneous suspension was obtained, copper hydroxide (7.47 mol) was added to the suspension. The entire mixture was stirred at 100 ℃ for 1 hour, then the temperature was raised and dried in vacuo.

The resulting melamine orthophosphate is converted to melamine polyphosphate in a furnace at 340 ℃. The product was then crushed to a fineness of 5 microns.

50% by weight of polyamide

Glass fiber 30% by weight

Melamine cyanurate 10% by weight

Melamine polyphosphate (prepared as above) 10% by weight

UL94 VO

Contrast (K value) 2.8

CTI 590V

The molding materials also have excellent flame resistance and laser writability (K value).

Claims (12)

1. Moulding material for producing highly flame-resistant articles, comprising a matrix formed from a thermoplastic and, dispersed in the matrix, a particulate flame-resistant pigment which changes colour under the influence of a laser or the colour of the plastic matrix and which is the reaction product of at least one halogen-free flame-resistant organic nitrogen base and a salt or salt mixture which is reactive with the organic nitrogen base, characterized in that the anion of the pigment has the general formula A_aO_o(OH)_y ^z-Wherein A represents trivalent or pentavalent phosphorus, tetravalent molybdenum orHexavalent tungsten, a, o and z independently represent an integer of 1 to 20, and y is an integer of 0 to 10, or the pigment contains a cyanurate anion as an anion.

2. A molding material as claimed in claim 1, characterized in that it has a pigment with a mean particle size (d)₅₀) Less than 10 microns.

3. A molding material as claimed in claim 1 or 2, characterized in that it has a pigment with an average particle size (d)₅₀) Less than 5 microns.

4. A molding material as claimed in claim 1, characterized in that the cations of its pigment consist of copper, tin, antimony, iron and/or boron.

5. A molding material as claimed in claim 1, characterized in that the anion of the salt contains phosphorus (V) acid and/or phosphorus (III) acid or condensation products thereof and the cation of the pigment consists of Cu and Fe, Cu and Sn, Cu and Sb, or Sn and Fe.

6. A molding material as claimed in claim 4, characterized in that the anion of the salt also has hydroxide ions.

7. A molding material as claimed in claim 1, characterized in that the salt is selected such that the non-irradiated pigment has an absorption in the wavelength region of the light to be used.

8. A moulding material as claimed in claim 1, characterized in that its thermoplastic matrix comprises polypropylene, polyethylene, polyamide, polybutylene terephthalate, polyethylene terephthalate, polyester, polyphenylene ether, polyacetal, polymethacrylate, polyoxymethylene, polyvinyl acetal, polystyrene, polyacrylic-butadiene-styrene (ABS), polyacrylonitrile-styrene-acrylate (ASA), polycarbonate, polyether sulphone, polyether ketone, polyvinyl chloride and thermoplastic polyurethane, optionally reinforced with glass fibres, and/or copolymers thereof and/or mixtures thereof.

9. A moulding material as claimed in claim 1, in which the halogen-free organic nitrogen base comprises melamine, melamine cyanurate, melamine orthophosphate, di (melamine) orthophosphate, melamine pyrophosphate, melamine polyphosphate, melamine borate, melamine salts of phosphoric acid partial esters, other salts of phosphorus oxide compounds having III-and V-valency, ammonium polyphosphate, boron phosphate and/or mixtures thereof and mixtures thereof with synergists.

10. A moulding material as claimed in claim 9, in which the synergist is selected from pentaerythritol, dipentaerythritol, THEIC, triazine polymers, urea, guanidine, melem, melam or phosphonates.

11. Use of the pigment according to claim 1 for the production of thermoplastic articles having high flame retardancy and laser-writability.

12. The pigment according to claim 1 for producing thermoplastic articles having both high flame retardancy and laser-writability.