Sealant Composition

Abstract

The present invention relates to a kneadable adhesive sealant composition comprising a first outer portion of a first material comprising an uncured reactive polymer or resin composition and a second inner portion of a second material comprising a curing agent capable of curing the uncured reactive polymer or resin composition, wherein the first portion substantially surrounds the second portion and a process for making the same.

Claims

1. A kneadable adhesive sealant composition, comprising: a first, outer, longitudinal portion of a first material; and a second, inner, longitudinal portion of a second material; wherein the first longitudinal portion substantially surrounds the second longitudinal portion along the length of the second longitudinal portion; wherein the first material comprises an uncured reactive polymer or resin composition and the second material comprises a curing agent capable of curing the uncured reactive polymer or resin composition; and wherein, on kneading the composition to form a substantially homogenous mixture, the first and second materials react to cure the polymer or resin composition, and thereby form an adhesive sealant.

2. The kneadable adhesive sealant composition of claim 1, wherein the curing agent is present in an amount sufficient to cure from about 50 to about 150% of the uncured reactive polymer or resin composition.

3. The kneadable adhesive sealant composition of claim 1 or 2, wherein the longitudinal portion of the first material and/or the second material have a circular, elliptical, rectangular or square cross-section.

4. The kneadable adhesive sealant composition of any preceding claim, wherein the longitudinal portion of the first material and the longitudinal portion of the second material each have a cross-section having an area of about 10 mm.sup.2 to about 500 mm.sup.2.

5. The kneadable adhesive sealant composition of any preceding claim, wherein the width of the kneadable adhesive sealant composition is about 5 mm to about 50 mm.

6. The kneadable adhesive sealant composition of any preceding claim, wherein the kneadable adhesive sealant composition is provided as a tape.

7. The kneadable adhesive sealant composition of any one of claims 1-5, wherein the kneadable adhesive sealant composition is provided as a stick.

8. The kneadable adhesive sealant composition of any preceding claim, wherein the kneadable adhesive sealant composition is surrounded by a protective coating, casing or film.

9. The kneadable adhesive sealant composition of any preceding claim, wherein the uncured reactive polymer or resin composition comprises an uncured epoxy resin.

10. The kneadable adhesive sealant composition of any preceding claim, wherein the curing agent comprises a polymercaptan amine curing agent.

11. The kneadable adhesive sealant composition of any preceding claim, wherein one or more lateral creases or scores (optionally perforated) are provided along the length of the kneadable adhesive sealant composition to divide the kneadable adhesive sealant composition into two or more segments,

12. The kneadable adhesive sealant composition of claim 11, wherein: a) the creases or scores are regularly spaced such that each segment has substantially the same shape; or b) the creases or scores are irregularly spaced such that more than one shape of segment is present.

13. A kneadable adhesive sealant composition, comprising: one or more, outer, envelopes of a first material; and a second, inner, material enclosed within the one or more envelopes of the first material surrounded by the first material; wherein the first material comprises an uncured reactive polymer or resin composition and the second material comprises a curing agent capable of curing the uncured reactive polymer or resin composition; and wherein, on kneading the composition to form a substantially homogenous mixture, the first and second materials react to cure the polymer or resin composition, and thereby form an adhesive sealant.

14. The kneadable adhesive sealant composition of claim 13, comprising the features of any one of claims 2 to 10.

15. The kneadable adhesive sealant composition of claim 13 or 14, wherein the kneadable adhesive sealant composition is provided as a tape.

16. The kneadable adhesive sealant composition of any one of claims 13 to 15, wherein the composition comprises two or more, outer, envelopes of the first material.

17. The kneadable adhesive sealant composition of claim 16, wherein: a) each envelope has substantially the same shape; or b) more than one shape of envelope is present.

18. A process for producing a kneadable adhesive sealant composition, comprising: providing a first material comprising an uncured reactive polymer or resin composition and a second material comprising a curing agent capable of curing the uncured reactive polymer or resin composition; and co-extruding the first and second materials to form the kneadable adhesive sealant composition of any one of claims 1 to 17.

19. The process of claim 18, wherein the first and second materials are co-extruded using a screw extruder.

20. The process of claim 18 or 19 where the process further comprises the step of covering the extruded kneadable adhesive sealant composition with a protective coating, casing or film.

21. The process of any one of claims 18 to 20, wherein the first and second materials are co-extruded through a die having a rectangular cross-section to form a kneadable adhesive sealant composition provided as a tape.

22. The process of any one of claims 18 to 21, further comprising the step of flattening the kneadable adhesive sealant composition to form a tape.

23. The process of any one of claims 18 to 22, further comprising the step of making one or more lateral creases or scores along the length of the kneadable adhesive sealant composition, to divide the kneadable adhesive sealant composition into two or more segments.

24. Use of the kneadable adhesive sealant composition of any one of claims 1 to 18 as an adhesive or in the maintenance or repair of a surface, for example a stone, ceramic, metal, wood or plastics surface.

25. A kneadable adhesive sealant composition, process or use as substantially described herein with reference to or as illustrated in one or more of the examples or accompanying figures.

Description

[0083] Embodiments are now described by way of non-limiting example to illustrate aspects and principles of the disclosure, with reference to the accompanying drawings.

[0084] FIG. 1 shows a side view cylindrical stick of a kneadable adhesive sealant composition of the invention.

[0085] FIG. 2 shows a) a side view of a tape of kneadable adhesive sealant composition of the invention; and b) a cross section of the tape taken along the dotted line in FIG. 2 a).

[0086] FIGS. 3a and 3b are graphs showing the adhesion performance of kneadable adhesive sealant compositions, with storage of the compositions over time.

[0087] FIGS. 4a and 4b are graphs showing the adhesion performance of kneadable adhesive sealant compositions, with storage of the compositions over time.

[0088] FIGS. 5a and 5b are graphs showing the adhesion performance of kneadable adhesive sealant compositions, with storage of the compositions over time.

[0089] With reference to FIG. 1, there is provided a kneadable adhesive sealant composition 100 provided as a cylindrical stick. The kneadable adhesive sealant is extruded through a circular die. The first longitudinal portion of a first material 101 is provided radially outward of the second longitudinal portion of a second material 102, such that the longitudinal portion of the second material is surrounded along its length by the longitudinal portion of the second material. This arrangement protects the air-sensitive second material from the air.

[0090] With reference to FIG. 2, there is provided kneadable adhesive sealant composition 200 provided as a tape having lateral creases 201 along the length of the tape to divide the tape into a number of segments or envelopes 202. FIG. 2 a) shows kneadable adhesive sealant composition 200 as extruded through a circular die and flattened by passing through a flattening roller to produce a tape. Alternatively, the kneadable adhesive sealant composition 200 may be extruded through a rectangular die to avoid the need for flattening. The longitudinal portion of the first material 101 surrounds the longitudinal portion of the second material 102 in the tape form and provides an outer layer to the tape.

[0091] FIG. 2 b) shows a cut through taken along the dotted line of FIG. 2 a) and illustrates the arrangement with the band of the first material 101 surrounding the band of the second material 102.

[0092] Sample Manufacture

[0093] Exemplary Manufacture Protocol

[0094] A two-part kneadable adhesive sealant composition according to the invention comprising a first material comprising an uncured reactive polymer or resin composition and a second material comprising an agent capable of polymerising or curing the uncured reactive polymer or resin composition may be produced using an extruder (for example, a screw extruder as sold by The Bonnot Company). Piston or ram extruders could also be used to produce the kneadable adhesive sealant composition.

[0095] The first material comprises between 35 and 50 wt % talc filler, up to 25 wt % silicon dioxide microspheres filler, between 5 and 35 wt % bisphenol-A-(epichlorohydrin) epoxy resin (having number average molecular weight of 700 Da), up to 5 wt % titanium dioxide, and up to 2.5 wt % di-isodecyl phthalate.

[0096] The second material comprises between 10 and 80 (preferably about 10 to about 60) wt % of a polymercaptan epoxy hardener, between 35 and 50 wt % talc filler, up to 25 wt % silicon dioxide microspheres filler, up to 1 wt % 3,6-diaxaoctanethylenediamine, between 0.1 and 15 wt % (preferably 0.5 and 3 wt %) aminophenol or 2,4,6-tris(dimethylaminomethyl)phenol and up to 2.5 wt % di-isodecyl phthalate.

[0097] The first and second materials were coextruded through a rectangular die head resulting in a two component concentric co-axial tape composition. The composition was extruded onto a protective barrier plastic film. The extruded composition was cut using a Flywheel Cutter (Goodman). A second layer of protective film was applied on top of the extruded composition. Product was then chilled to below about 10 C. to improve handling and finishing.

[0098] The composition and protective film were then scored using a die cutter to form perforated strips creating a sheet of attached individual use segments of the composition, which was then further cut to a predetermined finished length for packaging.

[0099] Stability of Kneadable Adhesive Sealant

[0100] The following experiment quantifies the degradation rate of the kneadable adhesive sealant composition of the present invention compared with co-extruded epoxy tapes known in the art. Lap shear adhesive strength was chosen to measure of the effects of temperature and aging on the degradation of the kneadable adhesive sealant composition. Lap shear adhesion is a primary performance character of adhesive systems and is sensitive to commonly encountered manners of degradation.

[0101] Sample Manufacture

[0102] Two sets of kneadable adhesive sealant compositions according to the invention were studied (the formulations BLUE TAPE 1 and BLUE TAPE 2). A batch of each of the first and second materials was made in a double arm kneader mixer. The same batches of materials were used to make all samples of the invention by co-extrusion using different die configurations to form kneadable adhesive sealant compositions of different dimensions.

[0103] To make a kneadable adhesive sealant compositions, a batch of each of the first and second materials was fed into the same co-extrusion system. Two different die configurations were used. The first die was a nominally 12.5 millimeters (mm) diameter circle and the second was a nominally 20 mm wide by 5 mm high rectangle.

[0104] The rectangular die was attached to the extrusion system to produce kneadable adhesive sealant compositions of substantially one dimension without any additional downstream shaping. This product is referred to in the following as the NATIVE TAPE.

[0105] The circular die was also used for the purpose of illustrating the invention. With the circular die, kneadable adhesive sealant compositions were as a cylinder of nominally 12.5 mm diameter. The cylindrical extrudate through a flattening roller, creating a nominally 20 mm wide tape. This product is referred to in the following as the FLATTENED TAPE.

[0106] Sample Conditioning

[0107] After preparation, the NATIVE TAPE products were stored in ambient lab conditions (20 C.2 C.). Additionally a sample of each of these was stored in a 50 C. oven for the duration of the experiment. The products stored under ambient conditions and in the oven were evaluated within one week of manufacture and then every two weeks thereafter.

[0108] Preparation of Test Bonds

[0109] Samples were taken from each of the products for analysis by cutting across the product in cross section using a razor blade. Each sample was mixed by kneading until the material attained a uniform color, and then for an additional minute. The mixed sample was then used to create two overlap bonds between two metal test panels provided by Q-Labs measuring nominally 100 mm by 25 mm by 1.5 mm. The test panels were cleaned with isopropyl alcohol and wiped with a lint free cloth. The mixed sample was applied to one end of the brushed finish side of each test panel. Two pieces of AWG 24 steel wire nominally 3 mm in length were embedded in the product that was applied to one of the panels. The other panel was pressed overtop to create an overlap bond. Bonds were clamped in place using two Pony 3201 One-Inch Steel Spring Clamps. During the clamping process, any excess product was squeezed out of the bond and discarded. This bond construction created a nominal 25 mm by 12.5 mm bond with a thickness of 0.5 mm. The time that each test specimens was completed was recorded.

[0110] Each product to be investigated was sampled three times, and each specimen was used to create two bonds. Six total bonds were created for each of the ambient conditions-stored products and the oven-stored products.

[0111] Evaluation of Test Bonds

[0112] After 242 hours of curing at ambient conditions (20 C.2 C.), the bond strength of bonded sample was evaluated, using a Tineous Olsen H25KS universal testing frame using a load cell with a 5000 pound-force capacity. The samples were evaluated in accordance with ASTM method D1002 with a specific cross-head speed of 0.05 inches per minute. Sample bonds were pulled in tensile stress until failure. The ultimate stress observed was recorded as the bond strength.

[0113] Analysis of Data

[0114] The data collected was analyzed to determine the rate of degradation at of the products stored at ambient conditions and in the 50 C. oven. The degradation model shown assumes a linear relationship between performance and age. This model is described below:

[0115] In the simplest case, the rate of degradation is constant with time.

[00001]$\frac{d.Math.y}{\mathrm{dt}}=k;$

[0116] Where y is the performance character to be investigated (in this case adhesion), t is time, and k is a constant.

[0117] Since the compositions can have a useful life of many years and the room temperature rate degradation may not be linear, it can take an undesirably long time to determine the degradation rate with the desired degree of accuracy. In most cases, the rate constant is a function of temperature. In some cases, the reaction rate k follows an Arrhenius behavior:

[00002]$k=A.Math.e^{\frac{-E_a}{R.Math.T}}$

[0118] Where A is a pre-exponential factor, Ea is an activation energy, R is the gas law constant, and T is the absolute temperature.

[0119] Using this relationship, the degradation rate at higher temperatures can be used to improve the accuracy of the ambient temperature degradation rate. In such a case the degradation study is carried out in an iterative manner and experiments conducted until enough data is collected to accurately model the degradation.

[0120] The results of the study are shown in FIGS. 3a and 3b. In the case of BLUE TAPE 1, the degradation rate at 50 C. (heat accelerated aging) for the NATIVE TAPE (FIG. 3b) is 4.9 psi of adhesive strength per day compared to a rate of 8.3 psi per day for the FLATTENED TAPE (FIG. 3a).

[0121] The average bond adhesion observed over time shows that kneadable adhesive sealants made from kneadable adhesive sealant compositions of the invention of the NATIVE TAPE kind degrade at a slower rate. Specifically, in the case of BLUE TAPE 1, these average degradation rates show the adhesive sealants made from the NATIVE TAPE are 40% more stable. The data for BLUE TAPE 2 shows similar trends.

[0122] Extended Aging

[0123] The average bond adhesion for both the BLUE TAPE 1 and BLUE TAPE 2 formulations were observed over a longer period of time and these results are shown in FIG. 4 for BLUE TAPE 1 (FIG. 4aFLATTENED TAPE; FIG. 4bNATIVE TAPE) and FIG. 5 for BLUE TAPE 1 (FIG. 5aFLATTENED TAPE; FIG. 5bNATIVE TAPE).

[0124] In the case of BLUE TAPE 1, the NATIVE TAPE showed a 35% improvement in degradation rate at 50 C. (heat accelerated aging) and 32% at 20 C. compared with the FLATTENED TAPE (Table 1).

TABLE-US-00001 TABLE 1 BLUE TAPE 1 FLATTENED (psi/day) NATIVE (psi/day) AVERAGE AVERAGE T ( C.) RATE lower upper RATE lower upper Improvement 20 0.5 0.16 1.61 0.34 0.2 0.87 32% 50 6.87 11.67 2.06 4.44 8.4 0.48 35%

[0125] In the case of BLUE TAPE 2, the NATIVE TAPE showed a 95% improvement in degradation rate at 50 C. (heat accelerated aging) and 84% at 20 C. compared with the FLATTENED TAPE (Table 2).

TABLE-US-00002 TABLE 2 BLUE TAPE 2 FLATTENED (psi/day) NATIVE (psi/day) AVERAGE AVERAGE T ( C.) RATE lower upper RATE lower upper Improvement 20 0.87 1.32 0.42 0.14 0.94 0.65 84% 50 1.92 4.86 1.02 0.1 1.7 1.49 95%

[0126] Throughout the description and claims of this specification, the words comprise and contain and variations of the words, for example comprising and comprises, mean including but not limited to, and are not intended to (and do not) exclude other components.

[0127] It will be appreciated that variations to the foregoing embodiments of the invention can be made while still falling within the scope of the invention. Each feature disclosed in this specification, unless stated otherwise, may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0128] All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the invention are applicable to all aspects of the invention and may be used in any combination. Likewise, features described in non-essential combinations may be used separately (not in combination).

[0129] It will be appreciated that many of the features described above, particularly of the preferred embodiments, are inventive in their own right and not just as part of an embodiment of the present invention. Independent protection may be sought for these features in addition to or alternative to any invention presently claimed.

[0130] While preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.