EP1893688A1

EP1893688A1 - Composite material containing wood and melamine resin

Info

Publication number: EP1893688A1
Application number: EP06791525A
Authority: EP
Inventors: Manfred Rätzsch; Andreas Endesfelder; Uwe Müller; Andreas Haider; Huong Lan Nguyen; Melanie Steiner
Original assignee: AMI Agrolinz Melamine International GmbH
Current assignee: AMI Agrolinz Melamine International GmbH
Priority date: 2005-06-20
Filing date: 2006-06-19
Publication date: 2008-03-05
Also published as: US20090174109A1; DE102005029685A1; RU2007146821A; CA2611199A1; WO2006136458A1

Abstract

The invention relates to composite material containing a proportion of wood and a proportion of cross-linked melamine resins, which is characterized in that the cross-linked melamine resins are formed from melamine resins that are, in essence, linearly synthesized and have a shear-dependent viscosity. The invention also relates to a method for producing the composite materials and to the use thereof.

Description

COMPOSITE MATERIAL CONTAINING WOOD AND MELAMIN RESIN

The invention relates to a composite material according to the preamble of claim 1, a method for its production according to claim 14 and its use according to claim 18.

Various composites containing plastics and wood have been described.

For example, composites made of wood and thermoplastics are known. EP 1 172404 B1 describes composites of polypropylene, polyethylene or polystyrene with a wood fiber content of 20 to 80% by weight. The disadvantage of thermoplastic-containing composites is the limited strength and toughness due to the poor compatibility of the apolar polyolefins with the wood component.

Mixtures of melamine resins and wood particles are also described above. Thus, JP 52 005 854 A2 sets out the use of wood powder as a filler in melamine molding compounds. A disadvantage of composites is their low flexibility due to the use of melamine resins.

The different melting and flow behavior of melamine resins also affects the properties of composites containing melamine resins.

To improve the viscosity and flexibility of composites with melamine resins, the addition of thermoplastics as a lubricant is known.

For example, WO 2005/009701 describes a composite of 55 to 90% by weight of wood particles and 45 to 10% by weight of crosslinked plastics, where the crosslinked plastics either crosslinked melamine resin ethers of melamine resins etherified with alcohols (MER type) or melamine resins remodeled with alcohols (type MPER ), or one

Mixture of partially crosslinked thermoplastics and crosslinked Melaminharzethern are. Preferred partially crosslinked thermoplastics are e.g. partially crosslinked ethylene-vinyl acetate copolymers, partially crosslinked polyethers and / or polyesters.

The addition of partially crosslinked thermoplastics makes it possible to obtain a homogeneous melt of the composite material with good flow properties, which is suitable for thermoplastic processing, for example in extruders. Disadvantageous for the use of such Composite material, however, affect the poor mechanical properties of the blended thermoplastics.

The invention is therefore based on the object to provide a composite material which has a good flow behavior and good compatibility between melamine resin and wood, while also showing good mechanical properties at the same time.

This object is achieved by a composite material with the features of claim 1.

The composite material according to the invention with a proportion of wood and a proportion of crosslinked melamine resins is characterized in that the crosslinked melamine resins are formed from melamine resins which have a substantially linear structure and a shear-dependent viscosity.

The essentially linear melamine resins are present as linear or weakly crosslinked chain molecules, which substantially correspond in structure to the melamine resins (melamine pigments) described in a parallel application. These chain molecules can slide together at a sufficiently high temperature, causing the resin to melt and show a dependence of viscosity on shear rate. This property is also called non-Newtonian behavior. Since these resins have a very good flow behavior in the melt phase, the wood particles can be distributed homogeneously in the resin matrix in the composite materials according to the invention. The addition of partially crosslinked thermoplastics as lubricants is no longer necessary. The composite material according to the invention is distinguished by good thermoplastic processability as well as improved mechanical properties.

The composite according to the invention advantageously comprises a proportion of wood of 40 to 85 wt .-%, a proportion of crosslinked melamine resins from 15 to 60 wt .-% and a proportion of additives from 0 to 20 wt .-%. Preferably, the composite material 50 to

80 wt .-% wood, 18 to 48 wt .-% crosslinked melamine resins and 2 to 10 wt .-% additives.

Advantageously, the melamine resins, which have a substantially linear structure and a shear-dependent viscosity, have molar masses of from 1000 to 200,000.

The composite of the invention preferably comprises melamine resins synthesized from triazine rings of the type (B ₂ N) ₆ -X- (NHA) ₃ wherein a + b = 3 and 0 <b <2, X is a triazine ring and A and Each B is a -CH ₂ OR - group with a radical R from represent any alkanol, diol or polyol. Non-crosslinked thermoplastics, lubricants or other additives such as flame retardants, pigments, stabilizers, catalysts, UV absorbers and / or free-radical scavengers as such or mixtures thereof may be used as additives.

A mixture of uncrosslinked thermoplastic and lubricant is preferably used as the additive, the amount of uncrosslinked thermoplastic being at most 20% by weight, based on the melamine resin in the composite material. This corresponds to a maximum thermoplastic content of 12% by weight, based on the composite material. At higher thermoplastic concentrations based on the melamine resin, the thermoplastic acts as a binder matrix. This means that the melamine resin is enclosed by the thermoplastic and this determines the mechanical properties of the composite.

Particularly preferred as the additive is a mixture of uncrosslinked thermoplastic and lubricant in an amount of not more than 5 wt .-% additive and a proportion of uncrosslinked thermoplastic of not more than 2 wt .-%, each based on the composite material used.

In principle, a wide variety of uncrosslinked thermoplastics can be used as an additive. Preferably in the composite ethylene vinyl acetate (EVA) or polycaprolactone are used as uncrosslinked thermoplastics.

Hydrocarbon waxes, oxidized hydrocarbon waxes, zinc stearate, calcium stearate, magnesium stearate or other metal soaps and / or mixtures are preferably used as lubricants.

The proportion of wood in the composite material according to the invention is advantageously in the form of wood flour, wood particles, wood granules, wood fibers and / or wood shavings.

It is preferred if the composite material according to the invention comprises fillers of the type melamine, urea, cellulose, urea-formaldehyde resins, melamine-formaldehyde resins,

Has polyether polyols and / or polyester polyols.

The composite material according to the invention is preferably in the form of a plate, profile or tube.

The object of the invention is also achieved by a method for producing a composite material according to claim 1 and its use.

The composite material according to the invention with a proportion of wood and a proportion of crosslinked melamine resins is prepared by a process, wherein - The wood, the substantially linear structure and a shear-dependent viscosity having melamine resins and additives are melted at temperatures of about 90 to 170 ⁰ C, homogenized and degassed, - the mixture is compressed at a melt temperature of about 100 to 150 ⁰ C,

- Is then introduced with elevation of temperature to 180 to 300 ⁰ C in a forming tool, in which the crosslinking takes place, and

- The finished composite material is discharged, and wherein the mixture between the compression part and the shaping part passes through a thermal separation stage, which prevents the heat transfer between the compression part and the shaping part.

Advantageously, the wood, the melamine resins and additives having a shear-dependent viscosity which are substantially linear in form, are melted, homogenized and degassed in an extruder, more preferably in a conical twin-screw extruder. It is also possible to use mixers or compounders for homogenizing, melting and degassing. The compression of the mixture takes place in the extruder.

The metering of wood, melamine resins and additives having substantially linear structure and a shear-dependent viscosity into the extruder, mixer or compounder is preferably carried out in the form of the individual components or in the form of a free-flowing mixture of the individual components.

The composites of the invention are preferably used in windows, doors,

Cladding elements and roof elements used outdoors, as well as in the sports and leisure sector for garden furniture, outdoor seating and playground design.

The invention will be explained in more detail with reference to several embodiments and figures. Show it:

FIGS. 1 a and 1 b: TEM images of a melamine-resin-thermoplastic mixture;

Figure 2 is a graph showing the viscosity of the melamine resin ether as a function of shear, and

Figure 3: a flowchart of the manufacturing process for a

Embodiment of the composite materials according to the invention. Embodiment 1

1.1 Preparation of wood melamine resin premixes

In a high speed mixer 17.6 kg of spruce-wood chips with 4.1 kg melamine resin, 0.54 kg of polycaprolactone and 3 wt% Naftosafe PHX 369D (Fa. CHEMSON), based on the total amount compounded at 90 ⁰ C for 8 min.

The melamine resin ethers are prepared on the basis of an MER (M: F = 1: 4), which are transetherified with 30% by weight of SIMULSOL® BPEP polyester polyol (Seppic) and treated with 50% by weight of MER (M: F = 1: 2.5) are compounded. The melamine resin ethers have an M _w of ~ 8000 g / mol and a shear-dependent viscosity of 45 Pa ^* s measured at 130 ⁰ C.

In the following, a further 4.1 kg of this melamine resin ether are metered into the premix and additionally mixed for 4 minutes. This mixture is cooled in the subsequent cooling mixer to about 40 ⁰ C and formulated.

1.2 Production of the cross-linked plastic product

In a Cincinnati extruder Fiberex T58 with conical twin screw, vacuum degassing and a plate tool (4.6 x 160 mm), the premix prepared under 1.1 is metered into the funnel at 35 kg / h and melted at 13O ⁰ C. In the following, this material is homogenized at a temperature profile in the extruder and tool of 130/130/130/110/110/110 /// 125/225/225/225 ⁰ C and cured.

Milled test pieces of the extruded wood-melamine resin composites have a density of 1.32 g / cm ³ and a flexural modulus of 72 N / mm ² .

Embodiment 2

2.1 Preparation of wood melamine resin premixes

16.2 kg spruce wood chips with 4.7 kg melamine resin ether, 1.35 kg polycaprolactone and 3 wt% Naftosafe PHX 369D (from CHEMSON), based on the total amount, are sintered at 95 ° C. for 9 minutes in a high-speed mixer. The melamine resin ethers are prepared on the basis of a MER (M: F = 1: 4), which are transetherified with 30% by weight of polyesterpolyol DESMOPHEN 800 (Bayer) and treated with 50% by weight of MER (M: F = 1 : 2.5) are compounded. The melamine resin ethers have an M _w of ~ 15,000 g / mol and a shear-dependent viscosity of 90 Pa ^* s measured at 130 ⁰ C.

In the following, a further 4.0 kg of this melamine resin ether are metered in and additionally mixed for 6 minutes. This mixture is cooled in the subsequent cooling mixer to about 50 ⁰ C and formulated.

2.2 Production of the cross-linked plastic product

In a Cincinnati - extruder Fiberex T58 conical twin screw, with vacuum degassing and plate mold (4.6 x 160 mm), in the feed hopper with 75 kg / h the premix prepared in 2.1 metered and melted at 125 ⁰ C. In the following, this material is homogenized and cured at a temperature profile in the extruder and tool of 125/125/125/120/120/120 /// 125/225/225/225 ⁰ C.

Milled test specimens of the extruded wood-melamine resin composites have a density of 1.29 g / cm ³ and a flexural modulus of 55 N / mm ² .

Embodiment 3

3.1 Preparation of wood melamine resin premixes

In a high-speed mixer are 16.2 kg spruce wood chips with 6.0 kg melamine resin ether, 1, 5 wt% Naftosafe PHX 369D and 1, 5 wt% Naftosafe PHX 369D20 (both from CHEMSON), in each case based on the total amount, at 105 ° C. Sintered for 9 minutes.

The melamine resin ethers are prepared on the basis of a MER (M: F = 1: 3), which are transesterified with 15% by weight of polyester polyol CAPA 3091 (SOLVAY). The

Melamine resin ethers have an M _w of ~ 10500 g / mol and a shear-dependent viscosity of 60 Pa ^* s measured at 130 ° C.

In the following, a further 4.0 kg of this melamine resin ether are metered in and additionally mixed for 6 minutes. This mixture is cooled in the subsequent cooling mixer to about 55 ° C and made up. 3.2 Production of the cross-linked plastic product

In a Cincinnati extruder Fiberex T58 with conical twin screw, with vacuum degassing and plate tool (4.6 x 160 mm), the premix prepared under 3.1 is metered into the hopper at 55 kg / h and melted at 110 ⁰ C. In the following, this material is homogenized and cured at a temperature profile in the extruder and tool of 110/110/1 10/110/110/110 /// 125/235/235/235 ° C.

Milled test pieces of the extruded wood-melamine resin composites have a density of 1.34 g / cm ³ and a flexural modulus of 68 N / mm ² .

Embodiment 4

4.1 Preparation of wood melamine resin premixes

In a high-speed mixer 18.9 kg beech wood chips with 0.54 kg of polycaprolactone and 3 wt% magnesium stearate based on the total amount, sintered at 97 ° C for 8 min. In the following, 6.75 kg of melamine resin ether are metered in and additionally mixed for 5 minutes.

The melamine resin ethers are prepared on the basis of an MER (M: F = 1: 3.5), which are transesterified with 15% by weight of Poy 1000 polyol Poyetherpolyol. The melamine resin ethers have an M _w of ~ 12000 g / mol and a shear-dependent viscosity of 73 Pa ^* s measured at 130 ⁰ C.

The wood-melamine premix is cooled in the subsequent cooling mixer to about 45 ° C and made up.

4.2 Production of the cross-linked plastic product

In a DS Weber extruder with parallel twin screw with vacuum degassing and plate mold (4.6 x 160 mm) is 13:27, in the feed hopper 70 kg / h the premix prepared in 4.1 metered and melted at 125 ⁰ C. In the following, this material is homogenized at a continuous temperature in the extruder of 125 ⁰ C and cured at 240 ⁰ C in the tool.

Milled test pieces of the extruded wood-melamine resin composites have a density of 1.25 g / cm ³ and a flexural modulus of 59 N / mm ² . Embodiment 5

5.1 Preparation of wood melamine resin premixes

In a high-speed mixer, 12.2 kg mixed wood chips with 7 kg of a melamine resin ether and 3 wt% Naftosafe THX 369D based on the total amount, sintered at 103 ⁰ C for 8.5 min.

The melamine resin ethers used are prepared on the basis of an MER (M: F = 1: 4), which are transetherified with 15% by weight of butanediol. The melamine resin ethers have an M _w of - 8000 g / mol and a shear-dependent viscosity of 50 Pa ^* s measured at 130 ° C.

In the following, a further 7 kg of the melamine resin ethers are metered into the premix and additionally mixed for 6 minutes. This mixture is cooled in the subsequent cooling mixer to about 50 ⁰ C and formulated.

5.2 Production of the cross-linked plastic product

In a Cincinnati single screw extruder Proton-25 B, with vacuum degassing and

Plate tool (4.6 x 160 mm) is metered into the hopper at 50 kg / h, the premix prepared under 5.1 and melted at 120 ° C. In the following, this material is homogenized at a continuous temperature in the extruder of 120 ⁰ C and cured at 230 ⁰ C in the tool.

Milled test specimens of the extruded wood-melamine resin composites have a density of 1.27 g / cm ³ and a flexural modulus of 63 N / mm ² .

Embodiment 6

6.1 Production of the cross-linked plastic product

In a Cincinnati extruder Fiberex T58 with conical twin screw, vacuum degassing and a plate tool (4.6 x 160 mm), the individual components are fed into the hopper at 40 kg / h:

• 26 kg spruce wood chips

• 12 kg melamine resin ether • 0.8 kg of polycaprolactone and

• 1, 2 kg Naftosafe PHX 369D (Fa. CHEMSON) metered by means of volumetric dosing and melted at 135 ⁰ C.

The melamine resin ethers are prepared on the basis of an MER (M: F = 1 A) which has been transetherified with 30% by weight of SIMULSOL® BPEP polyester polyol (Seppic) and 50% by weight MER (M: F = 1: 2.5 ) are compounded. The melamine resin ethers have an M _w of ~ 8000 g / mol and a shear-dependent viscosity of 45 Pa ^* s measured at 130 ⁰ C.

In the following, this material is homogenized and cured at a temperature profile in the extruder and tool of 135/135/120/110/1 10/110 /// 125/225/225/225 ⁰ C.

Milled test specimens of the extruded wood-melamine resin composites have a density of 1.29 g / cm ³ and a flexural modulus of 62 N / mm ² .

FIGS. 1a and 1b show TEM images of a melamine resin / thermoplastic mixture produced with CAPA®6400 thermoplastic (Solvay) with a magnification of 3900 times.

In Figure 1 a is the recording of a melamine resin / thermoplastic mixture (CAPA®6400, polycaprolactone, Solvay), wherein about 33 wt .-% CAPA®6400 were mixed. This corresponds to a ratio of MPER: CAPA®6400 of 2: 1. It can be seen clearly that CAPA®6400 (dark areas, lamellar structure) forms the matrix and the melamine resin (white areas) is embedded in it. The melamine resin is thus enclosed by the thermoplastic. As a result, the mechanical and thermal properties of the composite are determined by the thermoplastic, i. the composite is characterized by the poor mechanical properties of the thermoplastics not desired here.

FIG. 1b shows the inclusion of a melamine resin / thermoplastic mixture with about 17% by weight of CAPA®6400 and a ratio of MPER: CAPA® of 5: 1. The phase reversal is clearly recognizable, ie the melamine resin forms the matrix and the thermoplastic is embedded in the melamine resin (CAPA®6400, dark circles, lamellar structure). Thus, the mechanical properties of the composite are determined by the mechanical properties of the melamine resins, and thus the composite has improved hardness and durability.

FIG. 2 shows in a diagram the functional relationship between the viscosity of the melamine resin ether and shear, measured at 130 ^° C. It can be seen that the measured shear region is a nearly linear dependence of the viscosity of the shear rate, which is referred to as so-called non-Newtonian behavior.

FIG. 3 summarizes the steps for producing an embodiment of the composite material according to the invention. In a first step, wood, melamine resin and additives are melted in an extruder, mixer or compounder at temperatures between 90 to 170 ⁰ C, mixed, homogenized and degassed. In a second step, the compression of the mass in the extruder at 110 to 150 ⁰ C and carried out a thermal separation. In the next step, the mass is introduced into a molding tool at temperatures between 180 and 300 ⁰ C. This increase in temperature requires complete crosslinking and thus curing of the melamine resins. In a final step, the molded composite is discharged and cooled.

Claims

1Patentansprüche

1. Composite with a proportion of wood and a proportion of crosslinked melamine resins

characterized in that

the crosslinked melamine resins are formed from melamine resins which are substantially linear and have a shear-dependent viscosity.

2. Composite material according to claim 1 characterized by a proportion of wood from 40 to 85 wt .-%, a proportion of crosslinked melamine resins from 15 to 60 wt .-% and a proportion of additives from 0 to 20 wt .-%.

3. A composite material according to claim 1 or 2 characterized by a proportion of wood from 50 to 80 wt .-%, a proportion of crosslinked melamine resins from 18 to 48 wt .-% and a proportion of additives from 2 to 10 wt .-%.

4. Composite material according to at least one of the preceding claims, characterized in that the substantially linear structure and a shear-dependent viscosity having melamine resins have molecular weights of 1000 to 200,000.

5. Composite material according to at least one of the preceding claims, characterized in that the substantially linear structure and a shear-dependent

Melamine resins made of triazine rings of the type (B ₂ N) ₀ -X- (NHA) ₃ , where a + b = 3 and 0 <b <2, X is a triazine ring and A and B are each a -CH ₂ OR - group with one radical R from any alkanol, diol or polyol.

6. A composite material according to at least one of the preceding claims, characterized in that are used as additives uncrosslinked thermoplastics, lubricants or other additives such as flame retardants, pigments, stabilizers, catalysts, UV absorbers and / or free-radical scavengers as such or mixtures thereof.

7. A composite material according to at least one of the preceding claims, characterized in that a mixture of uncrosslinked thermoplastic and lubricant is used as the additive, wherein the amount of uncrosslinked thermoplastic is at most 20 wt .-% based on the melamine resin in the composite material.

8. A composite material according to at least one of the preceding claims, characterized in that the additive is a mixture of uncrosslinked thermoplastic and lubricant in an amount of not more than 5 wt .-% additive and a proportion of uncrosslinked thermoplastic of not more than 2 wt .-%, respectively based on the composite material is used.

9. A composite material according to any one of claims 6 to 8, characterized in that are used as unvemetzt thermoplastics ethylene vinyl acetate (EVA) or polycaprolactone.

10. A composite material according to at least one of the preceding claims, characterized in that are used as lubricants hydrocarbon waxes, oxidized hydrocarbon waxes, zinc stearate, calcium stearate, magnesium stearate or other metal soaps and / or mixtures thereof.

11. A composite material according to at least one of the preceding claims, characterized in that the proportion of wood in the form of wood flour, wood particles, wood granules, wood fibers and / or wood chips is present.

12. A composite material according to at least one of the preceding claims, characterized in that the composite material has fillers of the type melamine, urea, cellulose, urea-formaldehyde resins, melamine-formaldehyde resins, polyether polyols and / or polyester polyols.

13. Composite material according to at least one of the preceding claims, characterized in that it is present as a plate, profile or tube.

14. A method for producing a composite according to claim 1,

characterized in that

- the timber which is substantially linear structure and have shear-dependent viscosity comprising melamine resins and additives at temperatures of about 90 melted to 170 ⁰ C, are homogenized and degassed

- The mixture is compressed at a melt temperature of about 100 to 150 ⁰ C,

- Is then introduced with elevation of temperature to 180-300 ⁰ C in a forming tool, in which the crosslinking takes place, and

- the finished composite material is discharged, wherein the mixture between the compression member and the molding member undergoes a thermal separation step which prevents heat transfer between the compression member and the molding member.

15. The method according to claim 14, characterized in that the wood melamine resins and additives having substantially linear structure and a shear-dependent viscosity melted in an extruder, homogenized and degassed and the mixture is then compressed in an extruder.

16. The method according to claim 15, characterized in that the extruder is a conical twin-screw extruder.

17. The method according to claim 15 or 16, characterized in that the metering of wood, substantially linearly constructed and having a shear-dependent viscosity melamine resins and additives in the extruder in the form of the individual components or in the form of a produced free-flowing mixture of the individual components.

18. Use of composite materials according to at least one of claims 1 to 13 in windows, doors, cladding elements and roof elements in the outdoor area, as well as in

Sports and leisure sector for garden furniture, outdoor seating and playground design.