PUMPABLE, THERMALLY CURABLE AND EXPANDABLE PREPARATIONS

Abstract

A thermally expandable preparation pumpable at application temperatures in the range of 50 to 120° C., is provided containing: at least one polymer selected from binary copolymers containing at least one monomer unit selected from vinyl acetate, (meth)acrylic acids, styrene and derivatives thereof, and terpolymers based on at least one first monomer selected from the monounsaturated or polyunsaturated hydrocarbons, and at least one second monomer selected from (meth)acrylic acids and derivatives thereof, and at least one third monomer selected from epoxy-functionalized (meth)acrylates, as well as combinations of the first two; at least one liquid polymer selected from liquid hydrocarbon resins, liquid polyolefins and liquid polymers based on one or more diene monomers; at least one peroxide; at least one thermally activatable blowing agent; and at least one adhesion promoter; as well as methods to stiffen/reinforce or seal structural components by application of the preparation.

Claims

1. A thermally expandable preparation which can be pumped at application temperatures in a range of 50° C. to 120° C., and contains, in each case based on a total weight of the preparation: (a) 3 to 40 wt. % of at least one polymer, optionally comprising a peroxidically crosslinkable polymer, the at least one polymer being selected from: (a1) binary copolymers containing at least one monomer unit selected from vinyl acetate, (meth)acrylic acids, styrene and derivatives thereof, and (a2) terpolymers based on at least one first monomer selected from monounsaturated or polyunsaturated hydrocarbons, and at least one second monomer selected from (meth)acrylic acids and derivatives thereof, and at least one third monomer selected from epoxy-functionalized meth(acrylates); and combinations of (a1) and (a2); (b) 1 to 40 wt. % of at least one liquid polymer selected from: (b1) liquid hydrocarbon resins; (b2) liquid polyolefins; and (b3) liquid polymers based on one or more diene monomers; (c) 0.1 to 6 wt. % of at least one peroxide; (d) 0.1 to 20 wt. % of at least one thermally activatable blowing agent; (e) 1 to 12 wt. % of at least one adhesion promoter, selected from pre-crosslinked rubbers; and (f) 0 to 6 wt. % of at least one co-crosslinking agent selected from multifunctional (meth)acrylates.

2. The thermally expandable preparation of claim 1, wherein the at least one first monomer of (a2) comprises ethylene, the at least one second monomer of (a2) comprises (meth)acrylic esters, and the at least one third monomer of (a2) comprises glycidyl (meth)acrylate; and (f) is present in an amount of 0.1 to 3.5 wt. % and comprises low-molecular-weight multifunctional (meth)acrylates.

3. The thermally expandable preparation of claim 1, wherein the peroxidically crosslinkable polymer is present in (a1) and is selected from styrene-butadiene block copolymers, styrene-isoprene block copolymers, ethylene-vinyl acetate copolymers, functionalized ethylene-vinyl acetate copolymers, functionalized ethylene-butyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-butylacrylate copolymers, functionalized ethylene-butylacrylate copolymers, ethylene-(meth)acrylic acid copolymers and ethylene-2-ethylhexyl acrylate copolymers.

4. The thermally expandable preparation according to claim 3, wherein (a1) comprises an ethylene-vinylacetate copolymer; and the terpolymer (a2) contains ethylene as the first monomer unit, a (meth)acrylic ester as the second monomer unit, and a glycidyl (meth)acrylate as the third monomer unit.

5. The thermally expandable preparation according to claim 1, wherein the polymer (b) is selected from petroleum-based liquid hydrocarbon resins, polyisobutylene, butadieneisoprene copolymers, and combinations thereof.

6. The thermally expandable preparation according to claim 1, wherein said preparation contains a sulfonic acid hydrazide and/or azodicarbonamide as the blowing agent.

7. The thermally expandable preparation according to claim 1, wherein the adhesion promoter (e) is selected from butyl rubbers, optionally highly crosslinked butyl rubbers.

8. The thermally expandable preparation according to claim 1, wherein the preparation further comprises fillers, antioxidants, activators and/or dyes.

9. A method of stiffening and/or reinforcing a structural component or of sealing a cavity in a structural component, comprising applying the thermally expandable preparation according to claim 1 to a surface of the structural component to be reinforced or to a cavity surface of a structural component cavity to be sealed, at a temperature below 120° C., at a pump pressure of less than 200 bar; and subsequently curing the thermally expandable preparation at a later point in time, at temperatures above 130° C.

10. The structural component, optionally having a thin-walled structure, stiffened and/or reinforced and/or sealed according to the method of claim 9.

Description

EXAMPLES

1. Production of the Formulas

[0138] The following thermally expandable preparations were produced. Unless otherwise noted, the quantitative data are given in weight percent.

TABLE-US-00001 TABLE 1 Formulation Raw material F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 Lotader AX 8900 11.0 11.0 12.0 12.0 — 18.5 12.0 12.0 12.0 12.0 — Lotader AX 8700 — — — — — — — — — — 18.5 Elvaloy 4170 5.5 5.5 6.5 6.5 18.5 — 6.5 6.5 6.5 6.5 — Kuraray LIR 390 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 Novares TN 15 26.0 26.0 — — — — — — — — — Piccotac 1020 E — — 26.0 26.0 26.0 26.0 26.0 26.0 28.0 28.0 25.5 Oppanol B 10 N 5.3 — 5.3 5.3 5.3 5.3 5.3 5.3 6.3 6.3 6.3 Kalar 5275 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 4.0 2.0 Prododin B50/70 — 5.3 — — — — — — — — — Luzenac 2 11.5 11.5 11.5 11.5 11.5 11.5 12.0 12.0 12.0 16.0 20.0 Lamp Black 101 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Tracel OBSH 80PR 10.0 10.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.5 Trigonox 29-40B-GR-E 0.5 0.5 0.5 0.5 0.5 0.5 — — — — — Peroxan BIB-40P — — — — — — — — — — 1.0 Perkadox BC-40B/ 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 2.0 2.0 1.0 Peroxan DC-40GS SR350 3.0 3.0 3.0 3.0 3.0 3.0 SR351 3.0 3.0 2.0 2.0 2.0 Hostanox O3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 CaO Precal 30S 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 ZnO 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Total 100 100 100 100 100 100 100 100 100 100 100 Expansion rate (bead) in % F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 15 minutes, 160° C. 731 1006 743 540 680 368 443 631 651 626 573 15 minutes, 180° C. 696 806 659 527 672 374 549 651 621 538 601 40 minutes, 200° C. 578 669 405 410 403 311 570 532 554 491 493 Wash-off resistance 0 0 0 0 0 0 1 1 0 0 0 Melting point (° C.) 53.3- >75 >75 >75 >75 >75 >90 >90 64.5- 61.5- 54.1 65.5 62.4

2. List of the Commercial Products Used

[0139]

TABLE-US-00002 Lotader AX 8900 ethylene-acrylic ester-glycidyl methacrylate terpolymer, methyl (terpolymer) acrylate content 24 wt. %, glycidyl methacrylate content 8 wt. %, melting point 65° C., MFI 6 g/10 min (190° C., 2.16 kg) Lotader AX 8700 terpolymer (GMA/EBA), reactive ethylene terpolymer, 6-9 wt. % (terpolymer) glycidyl methacrylate, 23-28 wt. % butyl acrylate, melting point 72° C., MFI 7-11 g/10 min (190° C., 2.16 kg)) Elvaloy 4170 terpolymer (GMA/EBA), reactive ethylene terpolymer, 9 wt. % glycidyl (terpolymer) methacrylate, 20 wt. % butyl acrylate, melting point 72° C., MFI 8 g/10 min (190° C., 2.16 kg)) Kuraray LIR 390 liquid butadiene-isoprene copolymer, Mw 48,000, density 0.88 g/cm.sup.3 Novares TN 15 liquid hydrocarbon resin Piccotac 1020 E liquid low-molecular-weight hydrocarbon resin based on petroleum- based aliphatic monomers, Mw 1750, viscosity Brookfield LVTD, spindle 31 30,000 mPas (30° C.) acc. ISO 2555 Oppanol B 10 N liquid polyisobutylene, Mw 36,000, Mw/Mn 4.0 Kalar 5275 pre-crosslinked butyl rubber, Mooney viscosity ML 1 + 3 (127° C.) 65-72, density 0.92 g/cm.sup.3 Prododin B50/70 bitumen Luzenac 2 Talc, density 2.78 g/cm.sup.3, particle size 2-20 μm Lamp Black 101 carbon black, BET 21 m.sup.2 Tracel OBSH 80PR diphenyloxide-4,4'-disulfohydrazide, content 80%, decomposition (blowing agent) temperature approximately 160° C., gas yield 125 mL/g Trigonox 29-40B-GR-E 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, content 39-41 wt. %, 10.58% active oxygen, half-life temperature 1 h = 117° C., t90 = 145° C. (rheometer t90 approximately 12 min) di-(2-tert-butyl-peroxyisopropyl)benzene, content 39-41 wt. %, 3.78% Peroxan BIB-40P active oxygen, half-life temperature 1 h = 14° C., t90 = 175° C. (rheometer t90 approximately 12 min) Perkadox BC-40B/ dicumyl peroxide, content 39-41 wt. %, 5.92% active oxygen, Peroxan DC-40GS half-life temperature 1 h = 1138° C., t90 = 170° C. (rheometer t90 approximately 12 min) SR350 trimethylolpropane trimethacrylate TMPTMA, density 1.06 g/cm.sup.3, colorless liquid SR351 TRIMETHYLOLPROPANE TRIACRYLATE, density 1.1 g/cm.sup.3, Hostanox O3 bis[3,3-bis-(4'-hydroxy-3'-tert-butyl phenyl)butanoic acid]glycol ester, molecular weight 794 g/mol, melting point 167-171° C. CaO Precal 30S calcium oxide, > 97 wt. % content, bulk density 0.8 kg/dm.sup.3 ZnO zinc oxide, content > 99.5 wt. %, BET surface area 10 m.sup.2/g, density 5.47 g/cm.sup.3

[0140] To produce the thermally expandable preparations according to the invention, the polymers and resins contained were processed step-by-step with fillers at RT in a kneader or, if necessary, with heating to up to 150° C. to form a homogeneous dough. The other non-reactive components such as fillers, carbon black, stabilizers and plasticizers, if any, were then added one after the other and kneaded further until the formulation was smooth.

[0141] At below 60° C., all reactive components such as accelerators, peroxides, activators and catalysts, zinc oxide, calcium oxide and blowing agent were then added and slowly kneaded in until the adhesive was homogeneously mixed. Finally, the mixtures were homogenized for a further 10 minutes under a vacuum of less than 100 mbar and filled into cartridges.

3. Determination of the Properties of the Preparation

Determination of Expansion

[0142] To determine the expansion, test specimens having dimensions of approximately 20 mm×8-10 mmo round bead portions were pressed out of the cartridges produced from the example formulations at approximately 60-90° C. and these were introduced into a convection oven, which was heated to the temperatures specified in the tables (heating time approximately 7 to 10 minutes). The test specimens were then left at this temperature for the period specified in the tables (including heating time). The expansion at 180° C. corresponds to the ideal conditions that are achieved during curing in vehicle construction. The expansion at 160° C. simulates the underfiring conditions and the expansion at 200° C. simulates the overfiring conditions.

[0143] The degree of expansion [%] was determined by the water displacement method according to the formula

[00001]$\mathrm{Expansion}=\frac{\left(m2-m1\right)}{m1}\times 100$

m1=mass of the test specimen in its original state in deionized water
m2=mass of the test specimen determined after baking in deionized water.

Determination of Washout Resistance

[0144] To determine the washout resistance, round beads having a geometry of 150 mm×8-10 mmo were applied at 60-90° C. to a prepared metal sheet of approximately 200 mm×30 mm and cooled for at least 1 h. The metal sheet prepared in this way is clamped in a holder of a rod agitator having a 12 cm radius, and immersed in a bath at 55° C., the rod agitator is set to a speed of rotation of 60 min.sup.−1 and started. After 10 minutes the stirrer is switched off and the sample holder is lifted out of the water. The samples are removed from the holder and assessed. At least three test specimens are to be made.

[0145] The evaluation is based on the following rating scale:

0=unchanged compared with the initial state
1=little deformation
2=significant deformation without material washout
3=strong deformation, but without material washout
4=very strong deformation with material washout
5=material removal, but the originally wetted area is still covered with material
6=almost complete material removal except for small residual amounts