Modification of Asphalt Adhesives with Waxes

Abstract

Wax-modified asphalt can be employed in peel-and-stick sheets. In some embodiments, the method includes adding a wax to an asphalt blend. The addition of wax can result in an asphalt having lower viscosity, higher softening point, improved compatibility, and/or stronger adhesion properties. These changes can be achieved in addition to maintaining both low and high temperature stability of the asphalt adhesive. In some embodiments, the wax is made from a recycled plastic.

Description

FIELD OF THE INVENTION

The present invention relates to a method of employing waxes as additives in asphalt formulations used in asphalt adhesive products, such as peel-and-stick sheets, or ice and water shields.

Peel-and-stick sheets/mats are often used as a waterproof roofing underlayment, tile underlayment, and/or to protect foundations from water seepage.

When used as a roofing underlayment, the sheets are applied to the deck of a roof before the shingles to shield the deck fronom moisture, both before and after shingle installation. In at least some embodiments, the peel-and-stick sheets adhere directly to the plywood, or other material, that forms the structural portion of the roof. Often, when applied, the sheets smooth the outline of deck panels caused by irregularities in the deck surface that can be visible through the shingles. In addition, the sheets can help prevent flaming of the underside of the deck. One major component in peel-and-stick sheets is asphalt. Peel-and-stick sheets often are limited to the properties of the asphalt used.

Waxes can be employed to modify asphalt. Waxes are compatible with a wide variety of asphalt additives and can be combined with a variety of materials commonly employed to improve the quality of asphalts. However, the use of synthetic waxes designed from plastics to improve the physical properties, processability, and/or compatibility/stability of asphalt adhesive formulations has not yet been done.

There have been efforts to convert plastic feedstocks including solid wastes into useful products. One such process to form useful waxes from solid wastes is discussed in U.S. Pat. No. 8,664,458 “Kumar” which is hereby incorporated by reference herein in its entirety.

A method of employing waxes produced from thermal degradation and/or catalytic depolymerization of plastic feedstock to improve processing of and/or confer more desirable physical characteristics to asphalt adhesive formulations would be commercially advantageous. In some embodiments, such asphalt adhesive formulations can be used in peel-and-stick sheets and other asphalt applications.

SUMMARY OF THE INVENTION

A peel-and-stick sheet can comprise a top layer; a top compound layer containing a first asphalt formulation; a fiberglass mat layer; a bottom compound layer; and a plastic release film layer. In some embodiments, the top layer is a plastic film. In some embodiments, the top layer is made of a granulated material.

In certain embodiments, the first asphalt formulation contains a first wax. In some embodiments, the first wax is made by catalytic depolymerization of a polymeric material. In some embodiments, the first wax is made by thermally degrading a polymeric material.

In certain embodiments, the polymeric material is polypropylene. In some embodiments, the polymeric material is polyethylene. In some embodiments, the polymeric material is a mixture of polyethylene and polypropylene. In at least some embodiments, the polymeric material comprises recycled plastics.

In some embodiments, the bottom compound layer comprises a second asphalt formulation.

In some embodiments, the first asphalt formulation and the second asphalt formulation are the same.

In some embodiments, a peel-and-stick sheet can be created by adding a layer of asphalt, containing a wax made from depolymerized plastic feedstock, to the sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of peel-and-stick sheet.

FIG. 2 is a bar graph illustrating the penetration depth of various asphalt formulations at various temperatures.

FIG. 3 is a bar graph illustrating the softening point of various asphalt formulations.

FIG. 4 is a line graph illustrating the change in viscosity over the change in temperature for various asphalt formulations.

FIG. 5 is a bar graph illustrating adhesive strength of various asphalt formulations at various temperatures.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENT(S)

FIG. 1 is a side view of peel-and-stick sheet 100. In at least some embodiments, peel-and-stick sheet 100 can include top layer 110, top compound layer 120, fiberglass mat layer 130, bottom compound layer 140, and/or plastic release film layer 150.

In some embodiments, top layer 110 can be a plastic film. In some embodiments, top layer 110 can be a granulated material.

In at least some embodiments, top compound layer 120 can have an elastic modulus in compliance with the thermal and shear resistance requirements of ASTM D1970. In at least some embodiments, top compound layer 120 can be an asphalt. In some embodiments, top compound layer 120 can be modified with a wax.

In some embodiments, the wax can be made by catalytic depolymerization of polymeric material. In some embodiments, the wax can be made by thermally degrading polymeric material. In some embodiments, the polymeric material can be polyethylene. In some embodiments, the polymeric material can be polypropylene. In some embodiments, the polymeric material can be polypropylene (PP), high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or other variations of polyethylene.

In some embodiments, the polymeric material can include both polyethylene and polypropylene material. In some embodiments, the polymeric material can be divided evenly by weight between polyethylene and polypropylene. In some embodiments, the polymeric material can include lower levels of polystyrene, polyethylene terephthalate (PET), ethylene-vinyl acetate (EVA), (polyvinyl chloride) PVC, (ethylene vinyl alcohol) EVOH, and/or undesirable additives and/or contaminants, such as fillers, dyes, metals, various organic and inorganic additives, moisture, food waste, dirt, or other contaminating particles.

In some embodiments, the polymeric material can include combinations of LDPE, LLDPE, HDPE, and PP.

In some embodiments, the polymeric material comprises recycled plastics. In some embodiments, the polymeric material comprises virgin plastics. In other or the same embodiments, the polymeric material comprises recycled plastics and/or virgin plastics.

In some embodiments, the polymeric material can include waste polymeric material feed. Suitable waste polymeric material feeds can include, but are not limited to, mixed polyethylene waste, mixed polypropylene waste, and/or a mixture including mixed polyethylene waste and mixed polypropylene waste. The mixed polyethylene waste can include LDPE, LLDPE, HDPE, PP, and/or a mixture including combinations of LDPE, LLDPE, HDPE and PP. In some embodiments, the mixed polyethylene waste can include film bags, milk jugs or pouches, totes, pails, caps, agricultural film, and/or packaging material. In some embodiments, the waste polymeric material feed can include up to 10% by weight of material that is other than polymeric material, based on the total weight of the waste polymeric material feed.

In some embodiments, the polymeric material can be one of, or a combination of, virgin polyethylene (any one of, or combinations of, HDPE, LDPE, LLDPE and medium-density polyethylene (MDPE)), virgin polypropylene, and/or post-consumer or post-industrial polyethylene or polypropylene. Examples of post-consumer or post-industrial sources of polyethylene and polypropylene can include, but are not limited to, bags, jugs, bottles, pails, and/or other items containing PE or PP.

In at least some embodiments, bottom compound layer 140 can be modified. In at least some embodiments, bottom compound layer 140 can be an asphalt. In at least some embodiments, bottom compound layer 140 can function as the adhesive layer for the sheets. In at least some embodiments, bottom compound layer 140 can be formulated to firmly adhere to a variety of roofing decks. In at least some embodiments, the roofing deck is made of plywood. In at least some embodiments, the adhesive properties of bottom compound layer 140 can remain functional for months to allow for manufacture, warehousing, logistics and job-site storage prior to application. In at least some embodiments, the adhesive properties of bottom compound layer 140 can remain functional for at least six months after application.

In some embodiments, bottom compound layer 140 can be modified with a wax.

In some embodiments, top compound layer 120 can be modified with a wax. In some embodiments, top compound layer 120 is the same compound as bottom compound layer 140.

In some embodiments, the wax can be made by depolymerizing and/or thermally degrading polymeric material. In some embodiments, the polymeric material can include polyethylene. The polymeric material can be HDPE, LDPE, LLDPE, or other variations of polyethylene.

In other embodiments, the polymeric material can include polypropylene material. In other embodiments, the polymeric material can include both polyethylene and polypropylene material. In some embodiments, the polymeric material can contain up to 20% PP, lower levels of polystyrene, PET, EVA, PVC, EVOH, and/or undesirable additives and/or contaminants, such as fillers, dyes, metals, various organic and inorganic additives, moisture, food waste, dirt, or other contaminating particles.

In other embodiments, the polymeric material can include combinations of LDPE, LLDPE, HDPE, and PP.

In some embodiments, the polymeric material comprises recycled plastics. In other or the same embodiments, the polymeric material comprises recycled plastics and/or virgin plastics.

In some embodiments, the polymeric material can include waste polymeric material feed. Suitable waste polymeric material feed can include mixed polyethylene waste, mixed polypropylene waste, and/or a mixture including mixed polyethylene waste and mixed polypropylene waste. The mixed polyethylene waste can include LDPE, LLDPE, HDPE, PP, or a mixture including combinations of LDPE, LLDPE, HDPE and PP. In some embodiments, the mixed polyethylene waste can include film bags, milk jugs or pouches, totes, pails, caps, agricultural film, and packaging material. In some embodiments, the waste polymeric material feed includes up to 10% by weight of material that is other than polymeric material, based on the total weight of the waste polymeric material feed.

In some embodiments, the polymeric material can be one of, or a combination of, virgin polyethylene (any one of, or combinations of, HDPE, LDPE, LLDPE and medium-density polyethylene (MDPE)), virgin polypropylene, or post-consumer and/or post-industrial, polyethylene or polypropylene including, but not limited to bags, jugs, bottles, pails, and/or other items containing PE or PP.

In some embodiments, the addition of the wax can change the physical characteristics of the asphalt and the resulting sheets, including:

• • reducing the separation of liquid asphalt components when stored without agitation (with or without filler present);
  • increasing the adhesion strength to plywood;
  • increasing the softening point of asphalt;
  • stiffening the asphalt;
  • reducing the asphalt viscosity;
  • maintaining the low temperature flexibility of peel-and-stick sheets; and
  • maintaining thermal stability of peel-and-stick sheets.

In some embodiments, the percentage of wax in the wax/asphalt/filler/SBS/cross-linking agent compound is roughly 0-15% percent by weight.

The above method can employ a variety of waxes, including those with melt points between and inclusive of 60-170° C., and viscosities between and inclusive of 5-3000 cps. In some preferred embodiments, the wax(es) employed can have melt points between, and inclusive of, 115-170° C. and/or viscosities between, and inclusive of, 15-1000 cps.

Changes in melting point, viscosity, molecular weight, and/or polymer backbone structure of the wax can change the properties of the asphalt mixture.

Effect of Two Different Waxes on Selected Properties of Asphalt Mixture Used for Peel-and-Stick Sheet

As set forth in Table 1 and 2 below, Control Formulation consisted of 90% by weight of Base Asphalt (PRI Stock: Mid Continent) and 10% by weight of SBS (Kraton D1101).

TABLE 1
Sample Data Components
Ingredient	Grade/Type	Source
Base Asphalt	PG 64-22	PRI Stock
Asphalt Extender/Flux	Eco-Addz	Kleen Performance
		Products
SBS	3520	LCY
(styrene-butadiene-styrene)
Cross Linking Agent	Sulfur	PRI Stock
Dolomite Filler	#80 mesh (dried)	PRI Stock
Polyethylene Wax	Ceranovus A120	GreenMantra (Applicant)
Polypropylene Wax	Ceranovus A155	GreenMantra (Applicant)

The preparation of the four blends for testing in this example was as follows: first 75% by weight of base asphalt (PG 64-22) was mixed with 25% by weight of flux (Eco-Addz) to create an asphalt blend.

This blend was then mixed with various components including SBS, a cross linking agent (sulfur), a filler (#80 mesh), and/or various waxes (Ceranovus A120 and Ceranovus A155). The components of the formulations were mixed in the following order, asphalt blend, SBS, sulfur, wax (if any), and then filler. Data was taken after the addition of the sulfur, again after the addition of the wax, and again after the addition of the filler.

The softening point of the formulations were determined using method D36, the penetration of the formulations were determined using method D5, the viscosity of the formulations were determined using method D4402, the separation of the formulations were determined using method D7173, the thickness of the formulations were determined using method D5147, the flexibility of the formulations were determined using method D1970-7.6, the thermal stability of the formulations were determined using method D1970-7.5, and the adhesion to plywood of the formulations were determined using method D1970-7.4 according to the ASTM standards.

As set forth in Table 2 below, Control Formulation consisted of 72.5% by weight of Asphalt Blend; 7.5% by weight of SBS; 0.188% by weight of sulfur; and 20% by weight of filler.

Wax Blend Formulation 1 consisted of 72.5% by weight of Asphalt Blend; 5.5% by weight of SBS; 0.138% by weight of sulfur; 2% by weight of Ceranovus A120; and 20% by weight of filler.

Wax Blend Formulation 2 consisted of 72.5% by weight of Asphalt Blend; 5.5% by weight of SBS; 0.138% by weight of sulfur; 2% by weight of Ceranovus A155; and 20% by weight of filler.

Wax Blend Formulation 3 consisted of 70.5% by weight of Asphalt Blend; 7.5% by weight of SBS; 0.138% by weight of sulfur; 2% by weight of Ceranovus A155; and 20% by weight of filler.

TABLE 2
Sample Data Formulations
	Formulation
		Wax	Wax	Wax
	Control	Blend 1	Blend 2	Blend 3
Com-	Asphalt	72.5	72.5	72.5	70.5
ponent	Blend
% total	SBS	7.5	5.5	5.5	7.5
wgt	Sulfur	0.188	0.138	0.138	0.188
	Ceranovus	0	2	0	0
	A120
	Ceranovus	0	0	2	2
	A155
	Filler	20	20	20	20

TABLE 3
Properties After Addition of Sulphur & Before
Addition of Wax and Filler
		Formulation
			Wax	Wax	Wax
			Blend	Blend	Blend
		Control	1	2	3
Properties	Softening	102.2	89.4	90.6	101.7
	Point (° C.)
	Penetration at 25° C.	138	146	140	130
	(dmm)
	Viscosity at 170° C.	2020	660	800	2060
	(cPs)
	Viscosity at 190° C.	850	324	318	860
	(cPs)
	Separation of	109.8	102.2	100.2	107.5
	Top ⅓ via
	Softening
	Point (° C.)
	Separation of	88.1	79.4	79.4	87.2
	Bottom ⅓
	via
	Softening
	Point (° C.)
	Difference between	21.7	22.8	20.8	20.3
	Separation of
	Bottom and
	Top Thirds (° C.)

TABLE 4
Properties After Addition of Sulphur and Wax &
Before Addition of Filler
		Formulation
			Wax	Wax	Wax
			Blend	Blend	Blend
		Control	1	2	3
Properties	Softening	102.2	92.2	106.9	117.7
	Point (° C.)
	Penetration at 25° C.	138	121	102	99
	(dmm)
	Viscosity at 170° C.	2020	1080	970	2125
	(cPs)
	Viscosity at 190° C.	850	485	450	970
	(cPs)
	Separation of	109.8	104.8	109.1	115.5
	Top ⅓ via
	Softening
	Point (° C.)
	Separation of	88.1	80.9	115.2	123.2
	Bottom ⅓
	via
	Softening )
	Point (° C.
	Difference between	21.7	23.9	6.1	7.7
	Separation of
	Bottom and
	Top Thirds (° C.)

TABLE 5
Properties After Addition of Sulphur, Wax and Filler
		Formulation
			Wax	Wax	Wax
			Blend	Blend	Blend
		Control	1	2	3
Properties	Softening Point	98.9	93.3	108.3	119.8
	(° C.)
	Penetration at 25° C.	103	111	93	89
	(dmm)
	Viscosity at 170° C.	3875	1625	1270	2900
	(cPs)
	Viscosity at 190° C.	1160	540	560	1290
	(cPs)
	Separation	111.2	104.8	112.9	117.2
	of Top ⅓
	via Softening Point
	(° C.)
	Separation of Bottom	130.7	83.6	124.7	139.5
	⅓ via Softening
	Point (° C.)
	Difference between	19.5	21.2	11.8	22.3
	Separation of
	Bottom and Top
	Thirds (° C.)
	Thickness at 25° C.	1.264	1.520	1.348	1.358
	(mm)
	Flexibility at	Pass	Pass	Pass	Pass
	−28.9° C.
	Thermal Stability at	Pass	Pass	Pass	Pass
	70 +/− 1.1° C.
	Adhesion to Plywood	3.54	9.51	10.89	7.07
	at 4.4° C.
	Mean Force (lbf)
	Adhesion to Plywood	0.45	1.51	1.21	3.22
	at 4.4° C.
	Standard Deviation
	(lbf)
	Adhesion to Plywood	6.10	7.51	8.30	4.68
	at 23.9° C.
	Mean Force (lbf)
	Adhesion to Plywood	2.30	1.18	0.08	1.93
	at 23.9° C.
	Standard Deviation
	(lbf)

The following conclusions can be drawn from the above test results: additions of waxes made from either the thermal or catalytic degradation of PP and PE virgin or waste plastics to an asphalt adhesive formulation, such as a peel-and-stick formulation (either in addition to or to offset SBS rubber) provide the following benefits:

• • reducing the separation of liquid asphalt components when stored without agitation (with or without filler present);
  • increasing the adhesion strength to plywood;
  • increasing the softening point of asphalt;
  • stiffening the asphalt;
  • reducing the asphalt viscosity;
  • maintaining the low temperature flexibility of peel-and-stick sheets; and
  • maintaining the high temperature stability of peel-and-stick sheets.

More specifically, the addition of Ceranovus A120 (Wax Blend Formulation 1) increased adhesion to plywood by 23% at 23.9° C. and by 169% at 4.4° C. compared to the Control Formulation. Similarly, the addition of Ceranovus A155 (Wax Blend Formulation 2) increased adhesion to plywood by 36% at 23.9° C. and by 208% at 4.4° C. compared to the Control Formulation. This demonstrates that the addition of Ceranovus A120 or A155 improves the ability of the asphalt adhesive to adhere to plywood.

The addition of Ceranovus A120 and Ceranovus A155 improved viscosity by approximately 55-65%. This lower viscosity improves and facilitates production processes.

The softening point of the unfilled (Table 4) and filled (Table 5) formulations remained in the High Temperature (HT) compound range of most commercial products, (in the 200° F. range). The addition of Ceranovus A155 further improved (increased) the softening points.

The addition of Ceranovus A155 unexpectedly exhibited improved unfilled separation values (Table 4). Specifically, it is possible the Ceranovus A155 is acting as a compatibilizer. This is unexpected as a lower viscosity typically enhances tendencies to separate.

When Ceranovus A155 was added to the formulation without substitution of SBS, an improvement (increased) to the softening point and improvement to the (decreased) viscosity of the formulation while maintaining D1970's flexibility requirement was demonstrated. However, it's adhesion to plywood at 25° C. was reduced by 23%.

FIG. 2 is a bar graph illustrating the penetration depth of various asphalt formulations at various temperatures. Penetration was measured according to ASTM D5 standards.

FIG. 3 is a bar graph illustrating the softening point of various asphalt formulations. Softening points were measured according ASTM D36 standards.

FIG. 4 is a line graph illustrating the change in viscosity over the change in temperature for various asphalt formulations. Viscosity was measured according ASTM D4402 standards.

FIG. 5 is a bar graph illustrating adhesive strength of various asphalt formulations at various temperatures. Adhesion was measured according ASTM D1970-7.4 standards.

While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, that the invention is not limited thereto since modifications can be made without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.

Claims

1. A peel-and-stick sheet comprising: a) a top layer;b) a top compound layer comprising a first asphalt formulation;c) a fiberglass mat layer;d) a bottom compound layer; ande) a plastic release film layer.

2. The peel-and-stick sheet of claim 1, wherein said top layer is a plastic film.

3. The peel-and-stick sheet of claim 1, wherein said top layer is made of a granulated material.

4. The peel-and-stick sheet of claim 1, wherein said first asphalt formulation contains a first wax.

5. The peel-and-stick sheet of claim 4, wherein said first wax is made by catalytic depolymerization of a polymeric material.

6. The peel-and-stick sheet of claim 4, wherein said first wax is made by thermally degrading a polymeric material.

7. The peel-and-stick sheet of claim 5, wherein said polymeric material is polypropylene.

8. The peel-and-stick sheet of claim 5, wherein said polymeric material is polyethylene.

9. The peel-and-stick sheet of claim 5, wherein said polymeric material comprises recycled plastics.

10. The peel-and-stick sheet of claim 1, wherein said bottom compound layer comprises a second asphalt formulation.

11. The peel-and-stick sheet of claim 10, wherein said first asphalt formulation and said second asphalt formulation are the same.

12. A method of manufacturing a peel-and-stick sheet wherein a layer of asphalt is added to said peel-and-stick sheet wherein said asphalt contains a wax.

13. The method of claim 12, wherein said wax is made by catalytic depolymerization of a polymeric material.

14. The method of claim 12, wherein said wax is made by thermally degrading a polymeric material.

15. A peel-and-stick sheet comprising: a) a top layer;b) a top compound layer comprising a first asphalt formulation, wherein said first asphalt formulation comprises a first wax made from a depolymerized polymeric material;c) a fiberglass mat layer;d) a bottom compound layer; ande) a plastic release film layer.

16. The peel-and-stick sheet of claim 15, wherein said depolymerized polymeric material is polypropylene.

17. The peel-and-stick sheet of claim 15, wherein said depolymerized polymeric material is polyethylene.

18. The peel-and-stick sheet of claim 15, wherein said depolymerized polymeric material comprises a plurality of recycled plastics.

19. The peel-and-stick sheet of claim 15, wherein said bottom compound layer comprises a second asphalt formulation.

20. The peel-and-stick sheet of claim 19, wherein said first asphalt formulation and said second asphalt formulation are the same.