DE102017121725A1 - Surface material with the tribological properties of improving fillers - Google Patents

Abstract

The invention relates to a polyamide-based surface material having fillers which improve the tribological properties, wherein the fillers comprise at least one metal sulfide and / or calcium phosphate. Furthermore, the invention relates to a three-dimensional molded body consisting of a surface material, in particular as an injection molding or extrusion part and / or manufactured by additive manufacturing.

Description

The invention relates to a surface material based on polyamide with the tribological and in particular wear properties improving fillers.

Among other applications, such as gears and transmission components, surface materials are used as sliding materials, e.g. in plain bearings use.

Surface materials in the form of lubricating materials using polyamides are known in the art. For example, unfilled polyamide 4.6 is used, but it is not wear resistant enough for critical applications in the commercial vehicle sector.

In addition, a large number of other sliding materials are known which are based for example on PTFE and use polyamide only as a filler.

Something similar is for example in the DE 10 2011 077 008 A1 described which describes a sliding bearing composite material based on PTFE, in which fillers comprising thermoplastics and / or thermosets and other tribologically active substances together in compounded form in the polymer base of the sliding layer material.

In addition, for example, describes the DE 103 49 270 A1 a three-dimensional molded body for sliding load of a sliding layer material based on plastic, in particular PEEK, PPS or PA as matrix-forming plastic component, wherein zinc sulfide and / or barium sulfide and a curing component in the form of titanium dioxide and additional carbon fibers are used.

The use of polyamides as solid lubricants in solvent-free polyamideimide gleitlacken water-based has the DE 10 2013 021 949 A1 to the subject.

In addition to the use as a classic sliding material is another field of application for such surface materials for transmission parts, such as gears, which are subject to considerable wear due to the rubbing or rolling contact with a counterpart.

Based on this prior art, it was an object of the invention to improve the tribological properties and in particular the wear resistance of polyamide-based surface materials.

This object is achieved by a polyamide-based surface material having tribological properties improving fillers, wherein the fillers comprise one or more metal silicides and / or calcium phosphate.

Moreover, the invention relates to moldings and articles made of or with the Oberfächenmaterial invention.

It has surprisingly been found that the addition of one or more metal sulfides and / or calcium phosphate to the polyamide base significantly improves the wear resistance of the surface material. The present surface material is particularly suitable for uses outside the motor in the automotive sector, especially in grease-lubricated systems, such as transmission components, gears, commercial vehicle brake systems, Achsschenkellagerungen, etc. In such applications, there is a desire to use lead-free surface materials. The present surface material now provides a material that has sufficient wear resistance.

In the surface material of the present invention, a polyamide base is used as the polymer base. This does not necessarily mean that the entire polymer base must be 100% polyamide. Shares up to 30 wt .-% of the polymer content, in particular up to 20 wt .-% and preferably only up to 10 wt .-% of the polyamide base can by other polymers and combinations thereof, in particular PTFE, but also z. PVDF, PFA, FEP, ECTFE, ETFE. Preferably, the entire polyamide base consists of 100 wt .-% of polyamide.

According to a particularly preferred embodiment, it is provided that the polyamide base comprises PA 4.6 and in particular at least 60 wt .-%, in particular at least 70 wt .-%, in particular at least 80 wt .-%, in particular at least 90 wt .-% and in particular to 100 wt .-% of PA 4.6.

In addition, to further improve the properties of the surface material, in particular for better compounding of the materials, between 0 wt .-% and 40 wt .-%, in particular 1 wt .-% to 30 wt .-% and in particular 5 wt .-% bis 20 wt .-% of the polyamide base more of PA 4.6 different polyamides are used, in particular PA 6 and / or PA 6.6.

Particularly advantageous properties result when the proportion of the one or more metal sulfides and / or calcium phosphate in the sum of 1 wt .-% to 30 wt .-%, in particular 1 wt .-% to 20 wt .-% and in particular 5 wt. -% to 15 wt .-%, in particular 10 wt .-% of the surface material. Depending on the concrete selection of the fillers, it may also be particularly preferred if the proportion of calcium phosphate and / or metal sulfides is 5% by weight or 10% by weight, based in each case on the surface material.

It is particularly preferred if both the at least one metal sulfide and calcium phosphate are used. The proportion of the at least one metal sulfide is preferably 1 to 50% by weight and of calcium phosphate 50 to 99% by weight of the mixture of metal sulfide and calcium phosphate. In particular, the proportion of metal sulfide is from 3 to 40% by weight and calcium phosphate from 60 to 97% by weight. In particular, the proportion of metal sulfide is 5 to 30 wt .-% and calcium phosphate of 70 to 95 wt .-%.

Particular preference may be given to using mixtures of calcium phosphate and / or one or more metal sulfides, in particular MoS ₂ , SnS ₂ , WS ₂ or bismuth sulfide, and also combinations of the abovementioned.

Also particularly preferred is the use of WS ₂ without the addition of calcium phosphate.

• 2-20 Gew.-% SnS₂,
• 70-97 Gew.-% Calciumphosphat
• 1-10 Gew.-% WS₂.

Particularly preferred fillers have the following composition:

• 2-20% by weight SnS ₂ ,
• 70-97% by weight of calcium phosphate
• 1-10% by weight of WS ₂ .

The weights are based on the sum of the weights of the three fillers. The sum of the shares is 100% by weight. This composition can then be from 1 wt .-% to 30 wt .-%, in particular 1 wt .-% to 20 wt .-% and in particular 5 wt .-% to 15 wt .-%, in particular 10 wt .-% based on the weight of the surface material, be used in the surface material. Depending on the concrete selection of the fillers, it may also be particularly preferred if the proportion of calcium phosphate and / or metal sulfides is 5% by weight, based on the weight of the surface material.

• 50 Gew.-% Calciumphosphat
• 50 Gew.-% WS₂

bezogen auf die Summe der Gewichte der beiden Füllstoffe der Zusammensetzung.Another particularly preferred composition of fillers is

• 50% by weight of calcium phosphate
• 50% by weight of WS ₂

based on the sum of the weights of the two fillers of the composition.

Weight ratios of calcium phosphate to metal sulfide of 5: 1 to 1: 1 are particularly preferred.

• 1-3 SnS₂,
• 9-13 Calciumphosphat
• 1 WS₂,
• und insbesondere
• 1,67 SnS₂,
• 11 Calciumphosphat
• 1 WS₂.

For a preferred composition of the fillers of SnS ₂ / calcium phosphate / WS ₂ (in each case mass fractions based on the mass fraction of WS ₂ ), preferred proportions result as follows:

• 1-3 SnS ₂ ,
• 9-13 calcium phosphate
• 1 WS ₂ ,
• and particularly
• 1.67 SnS ₂ ,
• 11 calcium phosphate
• 1 WS ₂ .

Alternatively, particular preference is given to calcium phosphate and WS ₂ in a mass ratio of 1: 1 as fillers.

Such filler compositions offer particularly good tribological properties in such surface materials, in particular the wear properties of e.g. Plain bearings, sliding guides but also of gear parts or gears and transport chains and cable and chain guides positively influence.

Based on the mass of the surface material, the fillers may advantageously also have the following composition:
5% by weight of calcium phosphate and 5% by weight of WS ₂ .

In addition, it may also be advantageous to use only metal sulfides, in particular WS ₂ , as a filler, in particular with a proportion of 10% by weight, based on the surface material.

In addition, the fillers may comprise other tribologically active substances, for example reinforcing materials, in particular carbon fibers, glass fibers, polymer fibers (in particular aramid fibers); and / or solid lubricants, in particular PTFE, ZnS, BaSO ₄ , graphite, carbon black, BN and / or plastic particles, in particular aramid (PPTA), PPSO ₂ , PI and PAI particles, polyacrylate particles (PAR), PBA Particles, PBI particles; and / or metal oxides, in particular Fe ₂ O ₃ , Al ₂ O ₃ , SiO ₂ , CrO ₂ , TiO ₂ , CuO, MgO, ZnO; and / or hard material particles, in particular ceramic particles, such as SiC, Si ₃ N ₄ , BC, cubic BN; and / or fluorides, in particular CaF ₂ , NaF, AlF ₃ ; and / or sheet silicates, in particular kaolin, mica, wollastonite, talc, precipitated chalk, silicic acid; and / or metallic fine powders, in particular bronze and bismuth; and / or pigments or Mischphasenoxidpigmente, in particular Co-Al, Cr-Sb-Ti, Co-Ti, Fe-Al or Co-Cr.

It is particularly preferred if the proportion of other tribologically active substances 0 wt .-% to 40 wt .-%, in particular 1 wt .-% to 20 wt .-%, in particular 1 wt .-% to 10 wt. %, in particular 5 wt .-% of the surface material.

Particularly preferred is the use of phyllosilicates, in particular kaolin and / or wollastonite and / or talc, and / or solid lubricants, in particular BaSO ₄ and / or ZnS.

Furthermore, it is particularly preferred that the polyamide base 50 wt .- forms to 95 wt .-%, in particular 60 wt .-% to 95 wt .-% and in particular 70 wt .-% to 90 wt .-% of the surface material. In this way, the properties of the polyamide material can sufficiently affect the surface material.

The surface material can serve for producing a sliding bearing composite material with a metallic support layer, in particular made of steel or bronze, optionally with a porous support layer, in particular made of bronze and with a pore of the optional support layer filling and serving as a sliding surface material of the type described above the surface material is extruded with its fillers in a sheet-like flat material and this sheet is applied to a metallic support layer, or impregnated into the pores of the porous support layer, preferably a hot pressing process and / or a rolling process is used.

In addition, the invention also includes a three-dimensional molded body consisting of or with a surface material of the type described above, which is produced in particular as injection molding or extrusion. The molded body can also be added to a support member made of a different material, in particular be molded onto this. But there are also mechanical or other cohesive types of connection conceivable. Also, additive manufacturing methods are conceivable with which the molded body can be produced. The molded body can be used as a plain bearing element but also as a transmission component or e.g. be designed as a gear or find use.

The dimensions of the shaped body in each dimension are at least 1 mm, in particular at least 2 mm and more particularly at least 5 mm or at least 6 mm. Of course, the dimensions can also be much larger.

The sliding bearing composite material formed with the surface material or the three-dimensional molded body formed from or with the surface material can be used as sliding bearing element, wherein a sliding bearing element may be, for example, a sliding strip, a sliding block, a sliding pad and a sliding bearing shell, a plain bearing bush or a plain bearing bushing. In the case of a sliding shoe or a sliding strip, the dimensions of the shaped body in each dimension are at least 1 mm, in particular at least 2 mm and more particularly at least 5 mm or at least 6 mm. Of course, the dimensions can also be much larger. In principle, shell shapes, such as, in particular, spherical shell shapes, bushing or flanged bushes, as well as other components, are also conceivable in the use of the molded article.

Sliding elements may also be typically rolled cylindrical bushes or half-shell slide bearing elements made with the sliding bearing composite. The sliding bearing composite material can also be used for the production of flanged bushes or cup bushings or planar and spherical plain bearing elements.

The following table gives examples of a surface material serving as a sliding material. The wear values are in 1 shown. Example no. reference 1 2 3 4 5 100% by weight PA 4.6 80% by weight PA 4.6 85% by weight PA 4.6 80% by weight PA 4.6 80% by weight PA 4.6 75% by weight PA 4.6 polyamide-based 10% by weight PA 6.6 10% by weight PA 6.6 10% by weight PA 6.6 15% by weight PA 6.6 7.5% by weight of PTFE 5% by weight of PTFE fillers - - - 10% by weight of WS ₂ 10% by weight of mixture A 5% by weight of mixture A Other tribologically active substances - 10% by weight of kaolin 7.5% by weight of kaolin - - wear 174 189 117 83 71 64 Example no. 6 7 8th 9 10 polyamide-based 80% by weight PA 4.6 80% by weight PA 4.6 80% by weight PA 4.6 70% by weight PA 4.6 70% by weight PA 4.6 10% by weight PA 6.6 10% by weight PA 6.6 10% by weight PA 6.6 15% by weight PA 6.6 15% by weight PA 6.6 5% by weight of PTFE 5% by weight of PTFE fillers 5% by weight of calcium phosphate 5% by weight of WS ₂ 5% by weight of mixture A 5% by weight of mixture A 5% by weight of mixture A 5% by weight of mixture A Other tribologically active substances 5 wt .-% barium sulfate 5% by weight of zinc sulfide 5% by weight of kaolin 5% by weight talc wear 57 55 51 46 43

• 11 Anteile Calciumphosphat
• 1 Anteil WS₂

Mixture A: 1.67 parts SnS ₂

• 11 parts calcium phosphate
• 1 share WS ₂

The wear values in μm are in the following 1 plotted along with the parameters of the measurement:

1 It can be seen that the addition of fillers of the mixture A or the addition of calcium phosphate together with WS ₂ or the addition of WS ₂ alone as an exemplary metal sulfide significantly reduces the wear values and thus improves the wear resistance.

The examples 3 to 10 presented above represent preferred compositions of the surface material according to the invention, wherein the polyamide base is formed from two different polyamides with a focus PA 4.6 and partially PTFE and this shares of 5 wt .-% or 10 wt .-% of a mixture A of Tin disulfide, calcium phosphate and tungsten disulfide in a ratio of 5: 33: 3 wt .-% was added and some other tribologically active substance, such as 5 wt .-% barium sulfate, zinc sulfide, kaolin or talc in Examples 7-10. An alternative composition of the fillers is shown in Examples 3 and 6. Examples 1 to 2 are comparative examples. A surface material of PA 4.6 without fillers and other ingredients serves as a reference.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011077008 A1 [0005]
• DE 10349270 A1 [0006]
• DE 102013021949 A1 [0007]

Claims (19)

Polyamide-based surface material having tribological properties improving fillers, characterized in that the fillers comprise at least one metal sulfide and / or calcium phosphate. Surface material after Claim 1 , characterized in that the polyamide base of the surface material comprises at least 70 wt .-%, in particular at least 80 wt .-%, in particular at least 90 wt .-% and in particular 100 wt .-% polyamide. Surface material after Claim 1 or 2 , characterized in that the polyamide base PA comprises 4.6 and in particular at least 60 wt .-%, in particular at least 70 wt .-%, in particular at least 80 wt .-%, in particular at least 90 wt .-% and in particular to 100 wt .-% consists of PA 4.6. Surface material according to one of Claims 1 to 3 , characterized in that the polyamide base comprises 0-40% by weight, in particular 1-30% by weight and in particular 5-20% by weight, of further polyamides other than PA 4.6, in particular, PA 6 and / or PA 6.6 , Surface material according to one or more of the preceding claims, characterized in that the proportion of the at least one metal sulfide and / or calcium phosphate in total 1 - 30 wt .-%, in particular 1 - 20 wt .-% and in particular 5 - 15 wt. %, in particular 5 wt .-% or 10 wt .-% of the surface material. Surface material according to one or more of the preceding claims, characterized in that the weight ratios of calcium phosphate to metal sulfide are between 5: 1 and 1: 1. Surface material according to one or more of the preceding claims, characterized in that the at least one metal sulfide SnS ₂ , MoS _s , bismuth sulfide or WS ₂ and combinations thereof. Surface material after Claim 7 , characterized in that the fillers comprise the following composition: 2-20 wt .-% SnS ₂ , 70-97 wt .-% calcium phosphate 1-10 wt .-% WS ₂ . Surface material after Claim 7 or 8th , characterized in that the weight fractions of the fillers 1-3 SnS ₂ 9-13 calcium phosphate 1 WS ₂ , and in particular 1.67 SnS ₂ 11 calcium phosphate 1 WS ₂ amount. Surface material according to one or more of Claims 1 to 7 , characterized in that the fillers have the following composition based on the surface material: 5 wt .-% calcium phosphate 5 wt .-% WS ₂ . Surface material according to one or more of the preceding claims, characterized in that the fillers comprise further tribologically active substances and as further tribologically active substances reinforcing materials, in particular carbon fibers, glass fibers, polymer fibers (in particular aramid fibers); and / or solid lubricants, in particular PTFE, ZnS, BaSO ₄ , graphite, carbon black, BN and / or plastic particles, in particular aramid (PPTA), PPSO ₂ , PI and PAI particles, polyacrylate particles (PAR), PBA Particles, PBI particles; and / or metal oxides, in particular Fe ₂ O ₃ , Al ₂ O ₃ , SiO ₂ , CrO ₂ , TiO ₂ , CuO, MgO, ZnO; and / or hard material particles, in particular ceramic particles, such as SiC, Si ₃ N ₄ , BC, cubic BN; and / or fluorides, in particular CaF ₂ , NaF, AlF ₃ ; and / or sheet silicates, in particular kaolin, mica, wollastonite, talc, silicic acid; and / or metallic fine powders, in particular bronze and Bismuth; and / or pigments or mixed phase oxide pigments, such as, in particular, Co-Al, Cr-Sb-Ti, Co-Ti, Fe-Al or Co-Cr. Surface material after Claim 11 , characterized in that the proportion of other tribologically active substances 0- 40 wt .-%, in particular 1 - 20 wt .-% and in particular 1 - 10 wt .-%, in particular 5 wt% of the surface material. Surface material after Claim 11 or 12 , characterized in that as further tribologically active substances 0-40 wt .-%, in particular 1 - 20 wt .-% and in particular 1 - 10 wt .-%, in particular 5 wt .-% phyllosilicates, in particular kaolin and / or silica and / or solid lubricants, in particular BaSO ₄ and / or ZnS are provided. Surface material according to one or more of the preceding claims, characterized in that the polyamide base constitutes 50-95% by weight, in particular 60-95% by weight and in particular 70-90% by weight of the surface material. Sliding bearing composite material with a metallic support layer, in particular made of steel or bronze, in particular with a porous support layer, in particular of bronze, and with a pore of the support layer filling serving as a sliding surface material according to one or more of the above Claims 1 to 14 , A three-dimensional sliding load molded body consisting of or having a surface material according to one or more of the preceding Claims 1 to 14 , in particular produced as an injection molding or extrusion part and / or by additive manufacturing. Sliding element produced from a sliding bearing composite material Claim 15 or comprising a molding according to Claim 16 , Sliding element after Claim 17 , characterized in that it is a sliding strip, a sliding shoe or sliding pad or a sliding guide or a sliding bearing shell, a plain bearing bush or -bundbuchse. Sliding element comprising a molding after Claim 17 , characterized in that it is a gear, a transmission component, a cable or chain guide or a transport chain.

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