CH641826A5 - Sealants and adhesives for elastic seals and adhesions - Google Patents

Description

The invention relates to sealing compounds and adhesive materials for elastic seals and bonds made of crosslinkable resins or their precursors or their mixtures with the addition of finely divided powders made of polyethylene or polypropylene or a mixture of these two substances.

Elastic sealing compounds and adhesive materials e.g. For sealing expansion and connection joints in construction, for edge sealing of insulating glass panes, for sealing glazing and for bonding various materials in mechanical engineering are mainly based on a resin base of polysulfides, silicones, polyurethanes, but also from other resins such as Butyl rubbers, acrylic copolymers (especially acrylic terpolymers) or mixtures thereof.

The sealing compounds and adhesive materials listed for the application areas mentioned contain, in addition to the corresponding synthetic polymers or precursors of the polymers to be formed, plasticizers, fillers such as Calcite, heavy spade or quartz, pigments such as Titanium dioxide or carbon black, anti-aging agents and catalysts. Depending on the hardening mechanism, they harden through exposure to air humidity, through oxidation, polyaddition or drying.

Well-formulated elastic sealing compounds and adhesive materials should be easy to process and should result in elastic connections with high aging and weather resistance, good adhesion and high practical elasticity. In the case of joint seals in particular, a visually perfect, permanently sticky and crack-free surface without inhomogeneities is required.

In order to meet the requirement for optically homogeneous surfaces, a complete digestion and thus a good distributability of the fillers during the production of the elastic products is necessary. Despite intensive mixing, even with high-quality products, the fragmentation of existing filler agglomerates is not always complete, so that these clumps are noticeably noticeable in the fully formed joint or glue point.

With high-quality, commercially available, elastic sealants and adhesive materials, the requirements listed above for good adhesion and high practical elasticity are largely met. Due to the elasticity of the products used, adhesion errors or cracks within the masses can nevertheless occur in practice. Cause of the tears on the joint flanks or other substrates and the formation of cracks within the elastic products at higher elongation, e.g. caused by temperature fluctuations are the excessive cohesive forces between the individual particles and the polymer chains. In the event of expansion stresses, the joint flanks are subjected to excessive stresses, which lead to tearing.

After the cause of this defect had been identified, various attempts to improve the quality were carried out and products in which the cohesive forces were specifically reduced were offered. In the case of such products, the elasticity of the sealing compounds and adhesive materials was reduced by adding increased amounts of plasticizers, so that the substrate adhesion was increased and the formation of cracks within the elastic compound was reduced. For their part, however, these compositions have the disadvantages that they release plasticizers into the surrounding materials and tend to become permanently sticky, which is associated with an increased susceptibility to contamination.

It has now been found that sealing compounds and adhesive materials for elastic seals and adhesive bonding according to the invention largely avoid the disadvantages mentioned and result in products with very good application properties, in particular markedly improved adhesion properties, less tendency to cracking and perfect production possibilities.

The sealing compounds and adhesive materials according to the invention for elastic seals and bonds made of crosslinkable resins or their preliminary products or their mixtures are characterized in that they contain an addition of preferably 1 to 40% by weight of finely divided powders made of polyethylene or polypropylene, preferably with an average molecular weight (Weight average) from 1000 to 10,000, particularly preferably from 2000 to 5000, or a mixture with any mixing ratio of the two components. It is also possible to use mixtures of finely divided polyethylene and / or polypropylene powders of different molecular weights in one formulation, and copolymers of ethylene or propylene with olefins having 2 to 6 carbon atoms in the molecule or mixtures thereof. The polyethylene and / or polypropylene powders provided in the sealing compounds and adhesive materials according to the invention are preferably in a degree of distribution of from 0 to 200 μm, particularly preferably from 0 to 50 μm. High and low-pressure polyethylene are suitable as polyethylene, the latter being preferred .

After use, the crosslinkable resins or their precursors or their mixtures can be crosslinked by exposure to atmospheric moisture, by oxidation or by polyaddition.

At concentrations above 40% by weight, fatigue appears in the material with pre-permanent, dynamic stress. These are below I% by weight

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Advantages described above are generally not available. A preferred range is 5 to 30, especially 15 to 20 wt .-%.

Finely divided polyethylene waxes have been used e.g. used in varnishes and printing inks to achieve matt effects, to improve particle distribution, to increase viscosity and to avoid sedimentation (see: Color and varnish / 82nd year / No. 11/1976).

The main advantage of the sealing compounds and adhesive materials according to the invention is that the force-length change diagrams recorded with them according to DIN 53 455 result in a clearly flatter curve in all cases. Consequently, lower forces are to be used for all changes in length (stretching); the cohesive forces are reduced and the tensions on the joint flanks or other substrates are reduced.

The practical consequence of this measurable effect is a significantly lower frequency of an adhesion or cohesion error. In addition, the disadvantages listed above, which result from the fact that the fillers used in the production of sealing compounds and adhesive materials cannot be fully digested, are eliminated. The incomplete digestion can inevitably occur in particular if a certain process management, e.g. the action of high shear forces must be avoided is inevitable. The sealing compounds and adhesive materials made with polyethylene or polypropylene powders are completely homogeneous even under unfavorable production conditions.

The finely divided polyethylene or polypropylene powders contained in the sealing compounds and adhesive materials according to the invention must of course also be combined with the other constituents of the formulation, e.g. be contracted with plasticizers, fillers, catalysts, pigments, stabilizers, etc. They are chemically inert to the binders, i.e. they have no chemical interactions with them.

The sealing compounds and adhesive materials according to the invention are used in a conventional manner.

The subject matter of the application is intended to be explained in more detail in the following examples, without being restricted thereby.

example 1

Elastic sealant for insulating glass panes, two-component. Component I

40.00 g polysulfide (Thiokol type LP 32) 15.00 g dibutyl phthalate

15.00 g polypropylene powder, molecular weight: 10,000, partial

Cheers: 1-5 by 0.30 g colloidal sulfur

29.70 g natural, crystalline chalk, grain size 1-5 (in. 100.00 g

Component II 4.00 g manganese dioxide.

The polysulfide used has a viscosity of 40 Pas (400 poise) to Pas (500 poise), a water content of max. 0.2% and an average molecular weight of 2,000 to 50,000 (main part 10,000). It is the subject of U.S. Patent No. 2,466,963 to Thiokol Corp., J.S. Patrick, and H.R. Ferguson.

Polysulfides and additives, in particular fillers, which can generally be used can be found in US Pat. Nos. 3123495 and 3297630.

Example 2

Elastic sealant for sanitary joints, one-component.

40.0 ga, © -hydroxy-polydimethylsiloxane, viscosity: about 50

Pa.s (50000 cP)

20.0 g silicone oil, viscosity: about 1 Pa.s (1000 cP) 15.0 g polyethylene powder, molecular weight: 3000, part

Size: 1-15 um 5.0 g fumed silica, surface: approx. 150 m2 / g 16.0 g natural, crystalline chalk, grain size 1-20 um 4.0 g methyl-tri-cyclohexylamino-silane 100.0 g

Example 3

Elastic sealant for frame connection jointing, two-component.

Component I

35.0 g polysulfide (Thiokol Type LP 32) 20.0 g dibutyl phthalate

15.0 polyethylene powder, molar weight: 5000, particle size 5-40 pm

10.0 g polyethylene powder, mol weight: 3000, particle size:

5-40 p.m 0.1 g triethylenediamine 19.9 g kaolin, grain size 1-40 (in 100.0 g

Component II

3.0 g cumene hydroperoxide, desensitized.

Example 4

Elastic filler for crack sealing, two-component.

Component I

2.4 g hexanediol 46.9 g chlorinated paraffin, 56% by weight chlorine, liquid 1.2 g lead octoate

2.4 g of fumed silica, surface: about 150 m 2 / g of 47.1 g of polypropylene powder, molar weight: 5000, particle size: 20-40 μm

100.0 g

Component II

33.8 g of adduct of glycerol and about 50 moles of propylene oxide 6.1 g of tolylene diisocyanate.

Example 5

Tough hard tile adhesive, one component. 28.0 g diphenylmethane diisocyanate

52.0 g adduct of glycerol and about 25 moles of propylene oxide 5.0 g of asbestos fiber, fiber length: about 20 [in 10.0 g polyethylene powder, mole weight: 10000, particle size:

1-5 | j.m 5.0 g xylene 100.0 g

Example 6

Elastic sealant for building construction joints, two-component.

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35.0 g polysulfide (Thiokol Type LT 32) 5.0 g polypropylene powder, mol weight: 3000, particle size: 1-15 (in 20.0 g chlorinated paraffin, 56% by weight chlorine, liquid 1.0 g iron oxide black 0.2 g colloidal sulfur 10.0 g titanium dioxide

28.8 g natural, crystalline chalk, grain size 30-40 (in 100.0 g

Component II 4.0 g lead dioxide.

Example 7

Flexible insulating adhesive, two-component.

Component I 10.0 g diisodecyl phthalate

30.0 g polypropylene powder, mol. : 5000, particle size: 10-30 Jim 60.0 g of 2,2-dimethyl-propanediol-1.3.

100.0 g

Component II

195.0 g of benzene diisocyanate

580.0 g adduct of glycerin and about 25 moles of propylene oxide.

Example 8

Elastic sealant for glazing rebate sealing, one-component.

40.0 ga, co-hydroxy-polydimethyl-siloxane, viscosity: about s 50 Pas (50000 cP)

12.0 g polyethylene powder, molar weight: 5000, particle size: 5-40 (im

8.0 g polypropylene powder, mol weight: 3000, particle size: 2-20 [in i ° 7.0 g fumed silica, surface about 150 m2 / g 3.0 g triacetoxysilane

30.0 g silicone oil, viscosity about 1 Pas (1000 cP)

100.0 g

15 Example 9

Plasto-elastic sealing compound 60.0 g acrylic terpolymer e.g. Paraloid CS 1 from Rohm and Haas, Philadelphia 10.0 g xylene

20 19.0 g polypropylene powder, mol. : 2500, particle size: 30-40 p.m 2.0 g fumed silica, surface about 150 m2 / g 2.0 g ethylene glycol 7.0 g pine oil 25 100.0 g

G

Claims (6)

641 826 1.Sealing compounds and adhesive materials for elastic seals and bonds from crosslinkable resins or their precursors or their mixtures, that they are additives of finely divided polyethylene or polypropylene powder or powders of ethylene or propylene mixed polymer risates with olefins with 2 to 6 carbon atoms in the molecule or their Mixtures included. 2. Sealing compounds and adhesive materials according to claim 1, characterized in that they contain crosslinkable resins as polysulfides, silicones, polyurethanes, butyl rubbers, acrylic polymers or mixtures thereof. 2nd PATENT CLAIMS 3. Sealants and adhesive materials according to claim 1 or 2, characterized in that they contain the polyethylene and / or polypropylene powder individually or in any mixtures in concentrations of a total of 1 to 40 wt .-%. 4. Sealing compounds and adhesive materials according to one of claims 1 to 3, characterized in that the polyethylene and / or polypropylene powder contained therein have an average molecular weight (weight average) between 1000 and 10000, preferably between 2000 and 5000, and also polyethylene and / or polypropylene powder of different molecular weights can be used. 5. Sealing compounds and adhesive materials according to one of claims 1 to 4, characterized in that the polyethylene and / or polypropylene powders used have a particle size of 0 to 200 µm, preferably 0 to 50 µm. 6. Sealants and adhesive materials according to claim 1 made of acrylic copolymers, e.g. Acrylic terpolymers.