Dimensionally stable adhesive and its use for glue sticks

Abstract

A dimensionally stable adhesive can be applied at room or ambient temperature to substrate surfaces. It comprises at least one, or two or more, polyfin(s) prepared in the presence of metallocene catalyst and having a ring & ball softening point in the range from 50 to 165° C., a needle penetration number of <50×0.1 mm, and a melt viscosity, measured at a temperature of 170° C., in the range from 20 to 40 000 mPa·s. The adhesive is water- and solvent-free and is used as a glue stick in the form of sticks, blocks, figures, spheres or cones.

Description

EXAMPLES

The examples below are intended to illustrate the invention but are not such as to restrict it to these examples. All percentages are to be understood as weight percentages.

The melt viscosities were measured in accordance with DIN 53019 using a rotational viscometer.

The drop points were measured in accordance with ASTM D3954, the ring & ball softening points in accordance with ASTM D3104.

The needle penetration number (═NPN) was determined in accordance with ASTM D 1321.

The molar mass weight average M_w and the molar mass number average M_n were determined by gel permeation chromatography at a temperature of 135° C. in 1,2-dichlorobenzene.

The polyolefins 1 to 3 used in accordance with the invention, as set out in table 1, were prepared in accordance with the method specified in the documents.

EP 0 384 264 and EP 0 571 882, respectively. Polyolefin 4 was prepared from polyolefin 1 by means of peroxide-induced grafting with 3% by weight of maleic anhydride in accordance with EP 941 257, general instructions, examples 1 to 11.

TABLE 1
Polyolefins used
	Polyolefin 1	Polyolefin 2	Polyolefin 3	Polyolefin 4
Prepared as per	EP 0 384 264	EP 0 384 264	EP 0 571 882	EP 0 941 257
	gen. instructs.	gen. instructs.	ex. 3	gen. instructs.
	ex. 1-161)	ex. 1-162)		ex. 1-11
Type	Propylene-	Propylene-	Propylene	Polyolefin 1,
	ethylene	ethylene	homopolymer	grafted with 3%
	copolymer	copolymer		maleic
				anhydride
Softening/	833)	884)	1453)	803)
drop point
(° C.)
Viscosity at	180	11 500	101	240
170° C.
(mPa · s)
Mn	2760	8250	1980	2810
Mw	6320	19 110	3900	6460
1)Polymerization data: total ethylene used: 400 g, polymerization temperature: 75° C.
2)Total ethylene used: 350 g, polymerization temperature: 65° C.
3)Drop point
4)Softening point

TABLE 2
Example formulas (amounts in % by weight)
	Example
	1	2	3	4	5
	Polyolefin 1	40	40	55	50
	Polyolefin 2	20	20			60
	Polyolefin 3			5
	Polyolefin 4				10
	Sukurez SU 90	40		40
	Foral AX-E		40		40	35
	Plasticizer*)					5
	Softening point (° C.)	77	77	121	124	75
	NPN (×0.1 mm)	20	25	20	17	31
	*)amorphous copolymer of propylene and ethylene, prepared on the lines of EP 0 200 351, p. 13, tab. 2, example 5, visc./170° C. = 320 mPa · s.
	Sukurez SU 90: hydrocarbon resin from Kolon Chemical Company;
	Foral AX-E: hydrocarbon resin from Eastman Chemical Company

The raw materials listed in table 2 were melted in the proportions indicated and were mixed at a temperature of 180° C. The melt mixtures were poured into a cylindrical silicone mold having an internal diameter of 2 cm and a length of 5 cm. After cooling, the solid stick was removed from the mold.

By means of rubbing under gentle pressure, linear adhesive films were produced on copier paper, on household aluminum foil, and on an LDPE sheet. By pressing a counterpart sheet onto the adhesive film, stable bonds were produced between all conceivable combinations of paper, aluminum, LDPE, and polyester.

Claims

1. A dimensionally stable adhesive which can be applied at room or ambient temperature to a surface of a substrate, comprising at least one polyolefin prepared in the presence of a metallocene catalyst, wherein the at least one polyolefin has a ring & ball softening point in the range from 50 to 165° C., a needle penetration number of <50×0.1 mm, and a melt viscosity, measured at a temperature of 170° C., in the range from 20 to 40 000 mPa·s.

2. The dimensionally stable adhesive as claimed in claim 1, wherein the adhesive is water- and solvent-free.

3. The dimensionally stable adhesive as claimed in claim 1, wherein the at least one polyolefin has a drop point or ring & ball softening point in the range from 60 to 165° C.

4. The dimensionally stable adhesive as claimed in claim 1, wherein the at least one polyolefin has a number-average molar mass Mn in the range from 500 to 20 000 g/mol, and a weight-average molar mass Mw in the range from 1000 to 40 000 g/mol.

5. The dimensionally stable adhesive as claimed in claim 1, wherein the at least one polyolefin is a homopolymer of linear or branched 1-olefins having 3 to 20 carbon atoms or are olefin copolymers comprising linear or branched 1-olefins having 3 to 20 carbon atoms and, optionally, ethylene.

6. The dimensionally stable adhesive as claimed in claim 1, wherein the wherein the at least one polyolefin is a propylene homopolymer or copolymer of propylene with one or more further monomers selected from the group consisting of ethylene and linear or branched 1-olefins having 4 to 20 carbon atoms, the amount of structural units originating from polypropylene in the case of the copolymers being between 70% and 99.9%.

7. The dimensionally stable adhesive as claimed in claim 1, further comprising one or more polar-modified olefin homopolymers, copolymers or a mixture thereof.

8. The dimensionally stable adhesive as claimed in claim 1, wherein the amount of the at least one polyolefin is in the range from 2% to 100% by weight.

9. The dimensionally stable adhesive as claimed in claim 1, further comprising one or more resins in an amount in the range from 0% to 60%.

10. The dimensionally stable adhesive as claimed in one claim 1, further comprising one or more plasticizers.

11. The dimensionally stable adhesive as claimed in claim 1, further comprising an additional, a polar or polar, polyolefin, wax, colorant, filler, stabilizer, antioxidant or a mixture thereof.

12. A glue product comprising the dimensionally stable adhesive as claimed in claim 1.

13. The dimensionally stable adhesive as claimed in claim 1, wherein the melt viscosity, measured at a temperature of 170° C., of the at least one polyolefin is from 50 to 30 000 mPa·s.

14. The dimensionally stable adhesive as claimed in claim 1, wherein the melt viscosity, measured at a temperature of 170° C., of the at least one polyolefin is from 10 to 20 000 mPa·s.

15. The dimensionally stable adhesive as claimed in claim 1, wherein the at least one polyolefin has a drop point or ring & ball softening point in the range from 70 to 150° C.

16. The dimensionally stable adhesive as claimed in claim 1, wherein the at least one polyolefin has a drop point or ring & ball softening point in the range from 80 to 140° C.

17. The dimensionally stable adhesive as claimed in claim 1, wherein the at least one polyolefin has a number-average molar mass Mn in the range from 800 to 10 000 g/mol, and a weight-average molar mass Mw in the range from 1600 to 30 000 g/mol.

18. The dimensionally stable adhesive as claimed in claim 6, wherein the the amount of structural units originating from polypropylene in the case of copolymers being between 80% and 99% by weight.

19. The dimensionally stable adhesive as claimed in claim 1, wherein the amount of the at least one polyolefin is in the range from 30% to 90% by weight.

20. The dimensionally stable adhesive as claimed in claim 1, wherein the amount of the at least one polyolefin is in the range from 40% to 70% by weight.

21. The dimensionally stable adhesive as claimed in claim 1, wherein the amount of the at least one polyolefin is in the range from 50% to 60% by weight.

22. The dimensionally stable adhesive as claimed in claim 1, further comprising one or more resins in an amount in the range from from 10% to 50% by weight.

23. The dimensionally stable adhesive as claimed in claim 1, further comprising one or more resins in an amount in the range from 20% to 40% by weight.

24. The glue product as claimed in claim 12, wherein the glue product is in the form of a stick, block, figure, sphere or cone.