GB1580871A - Method of providing a coating material including asphalt for application to a surface - Google Patents

Description

(54) A METHOD OF PROVIDING A COATING MATERIAL INCLUDING ASPHALT FOR APPLICATION TO A SLRFACE (71) We, H. C. PRICE CO., a corporation organized under the laws of the State of California, United States of America, of Price Tower, Bartlesville, Oklahoma, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of pro- viding coating material including asphalt for application to a surface.

Corrosion protective coatings for pipe of all sizes and types are well known in the industry. In many instances the corrosion coating is applied in a coating yard and the coated pipe then shipped to the job site where the individual pipe sections or joints are welded together to form the continuous pipeline. To permit welding of the joints together, an area of several centimeters at each end of the pipe joint is left free of the corrosion coating. When two joints of pipe are welded together, an area at the weld joint of approximately one meter in length will be free of the corrosion coating. It is thus necessary to apply a so-called field joint of coating material to this uncoated area.

For many years it was the practice in the industry to supply the components for the field joint coating material separately in relatively large packages or containers. The components were then mixed at the job site to prepare the field joint coating material. More recently, an effort has been made to supply the contractor with a premixed field joint coating material which need only be melted to a flowable liquid to prepare it for application at the job site.

Such prepackaging was initially done in cardboard or similar containers which needed to be removed before the premixed coating material could be melted into a flowable liquid.

Removal of the paper containers has been found to be a time consuming manual job and disposal of the containers is also likely to pre sent problems, especially when pipe is being laid from an offshore lay barge.

It is, therefore, a primary object of the present invention to provide a weld joint coating material for pipe contained in a container which can be amalgamated into the coating material.

Still another object of this invention is to provide a method of delivering coating material for the weld joints of pipe utilizing the container of the present invention, whereby it is not necessary to remove the container from the material when preparing the coating composition.

According to the present invention there is provided a method of providing coating material for application to a surface, said method comprising the steps of providing a plurality of individual containers filled with a coating material in solid form and including asphalt, each of which containers has a weight of no more than 5% by weight of the coating material contained therein, and each of said containers consists essentially of at least one plastics material selected from polyethylene, polypropylene, and ethylene-propylene copolymer; chopping up said containers containing said coating material to produce a mixture of particles of said container and said coating material; raising the temperature of said mixture to melt said container particles and said asphalt and produce a flowable liquid; and stirring the liquid to distribute the melted container particles homogeneously throughout the melted asphalt.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a top plan view of a container constructed to enable the present invention to be carried out; Figure 2 is a bottom plan view of the container shown in Figure 1; and Figure 3 is a horizontal, cross-sectional view taken along line 3-3 of Figure 2.

The coating material used for covering the weld joints of pipe coated with asphalt base corrosion coating may be between 10% to 25% by weight asphalt and 75% to 90% by weight aggregate. Any one of Grades I, II, or III asphalt (Asphalt Institute, specification series No. 7) is acceptable.

The asphalt will have an operating temper ature of no less than about 1200F. and a softening point of no less than about 150 F.

(ring and ball ASTM standard testing procedure).

The flash point of the asphalt is about 450 F.

The preferred material is Grade II asphalt which has an operating temperature of 150 F. and a softening point of 175 to 100 F.

The aggregate is preferably a 50-50 by weight mixture of sand and crushed limestone.

The sand is preferably fine enough to pass 100% through a 6 mesh screen (U.S.A.

Standard Testing Sieve). The crushed limestone is preferably fine enough for 100% to pass a 50 mesh screen and at least 75% by weight should pass a 200 mesh screen (both U.S.A.

Standard Testing Sieve). Other equivalent materials may be used as the aggregate filler and it may be found desirable to incorporate small amounts of other materials to enhance the physical properties of the coating. For example, 0.1 to 0.15% by weight of glass fiber may be added for additional reinforcement and strength.

The sand and lime aggregate are directed to a batch mixing station where they are homogeneously dispersed throughout the asphalt which has been heated to a fluid state. When the coating material has been satisfactorily combined, a batch is deposited in individual containers 10, each of which is designed to hold about 50 pounds. The containers with solidified coating material therein may be easily transported to a pipe laying spread or lay barge for use by the pipeline contractor. By filling containers 10 to no more than about one inch from the top, the filled containers are easily and stably stacked one on top of the other. A number of containers may be stacked on a pallet in this manner for handling by conveyors and forklift equipment.The containers 10 are constructed from a material comprising one or more of the following: polyethylene, polypropylene or ethylene-propylene copolymer. The total weight of the container should be no more than 5% of the weight of the coating material contained thereby. A preferred formulation for the containers is 10% to 15% by weight polyethylene, 10% to 15% by weight polyethylene-polypropylene copolymer and 70% to 80% by weight polypropylene. In the preferred form, each container 10 comprises 1% to 2% of the weight of the coating material contained thereby.

Each container 10 is preferably injected molded into a generally rectangular configuration including a bottom wall 12, side-walls 14 and a circumscribing peripheral lip 16 extending outwardly from the uppermost terminal edge of the sidewalls. Sidewalls 14 are disposed at an acute angle relative to bottom wall 12, thereby presenting a slightly tapered configuration. From viewing Figure 2, it is seen that each of the corner sections 18 joining sidewalls 14 is rounded. A concave dimple 20 in bottom wall 12 facilitates removal of the molded container from its mold.

A peripheral lip 16 which is of generally L-shaped cross-sectional configuration provides reinforcing for the sidewalls 14 and is supported throughout its length by spacedapart generally planar web portions 22 which extend between the outer leg of the lip and the adjacent wall 14. It is to be noted that lip 16 is of uniform width along its length except for those portions which are adjacent corner sections 18. In the area of corners 18, the lip is slightly wider so as to compensate for the rounded corner and to present a uniform external dimension of the container. In addition to reinforcing the container, lip 1 6 serves as a convenient handhold for workers to lift the container.The tapered configuration of sidewalls 14 permits multiple containers to be stacked or 'nested' one inside of the other, thereby greatly conserving the space required for shipping empty containers. To this end, the lip 16 serves another function of permitting the containers to be easily separated when nested one within the other, particularly after long periods of time when the containers may have somewhat of a tendency to adhere to one another.

Other equivalent formulations for the containers may be utilized although the melt flow index of the polymers and/or copolyers selected should preferably be 3.5 to 5.0 (ASTM).

Trace amounts of impurities, such as may be found in reclaimed plastics, generally will have no detrimental affect.

The containers 10 with the coating material contained therein are fed into a conventional chopper to reduce their size. In the interest of brevity, the chopper will not be described in detail but suffice it to say that a device of the type commonly used to chop tree limbs may be employed. The size of the resulting particles of container and coating material is not critical, although the particles should be sufficiently small to readily melt in a short period of time.

Next, the chopped particles are directed to a melt kettle where they are mixed as the temperature is raised to melt the particles and present a flowable liquid. A temperature of 300"F. to 4000F is suggested for melting the container material into the asphalt. A temperature of about 375"F. is preferable. It has been found that, when a plastic material such as polyethylene, polypropylene, or polyethylene-polypropylene copolymer is attempted to be amalgamated into pure asphalt, it is not practical to achieve adequate melting and distribution of the plastic, in any reasonable time, when operating at temperatures below 400 F. If the temperature is raised above 400"F., there is an ever present danger of reaching the flash point of the asphalt. With the present invention, however, it has been found that the plastic container material may be amalgamated in the asphalt following the procedure outlined above in a relatively short time.

Tensile Flexural Props Compressive Crack Strength (p.s.i,) Props (p.s.i.) Time (p.s.i.) Strength Modulus Yield Ultimate Sec Standard Asphalt Coating* Material 140 233 35911 135 168 91 Asphalt Coating* Material with Container Plastic* 192 287 39489 217 258 78 * according to the preferred embodiment of the invention Generally, utilizing a mixing tank of 2 tons capacity, the mixing time should be no less than about 45 minutes. Under normal conditions, a maximum melt time is one hour. It is thought that the presence of the aggregate filler material in the asphalt has a shearing action on the plastic and is the reason why the container material may be readily amalgamated into the asphalt.

It has also been found that the presence of the container material in the coating material increases some of the physical properties of the final pipe coating. Above is a comparative analysis showing cured coating material without the container material present and with the presence of 1.7% container material.

From the foregoing, it is apparent that the present invention provides for a substantially improved container for asphalt base pipe coating material and with an improved pipe coating resulting from amalgamation of the container into the coating material.

Reference is made to co-pending Divisional Application No. 26731/78 (Serial No. 1580872) which describes and claims the above container, and this divisional specifically claims a coating material package comprising a rigid container housing an asphalt base corrosion protective pipe coating, said coating comprising 10% to 25% by weight asphalt and 75% to 90% by weight aggregate, said container presenting a rigid configuration comprising sidewalls and a bottom; said container comprising no more than 5% by weight of the coating material contained therein, said container being constructed from a material comprising at least one of the members of the group consisting of polyethylene, polypropylene and ethylencpropylene copolymer.

WHAT WE CLAIM IS: 1. A method of providing coating material for application to a surface, said method comprising the steps of providing a plurality of individual containers filled with a coating material in solid form and including asphalt, each of which containers *as a weight of no more than 5% by weight of the coating material contained therein, and each of the said contain ers consists essentially of at least one plastics material selected from polyethylene, polypropylene, and ethylene-propylene copolymer; chopping up said containers containing said coating material to produce a mixture of particles of said container and said coating material; raising the temperature of said mixture to melt said container particles and said asphalt and produce a flowable liquid; and stirring the liquid to distribute the melted container particles homogeneously throughout the melted asphalt.

2. A method as claimed in Claim 1, wherein said temperature raising step raises said temperature to 3000 to 4000 F.

3. A method as claimed in Claim 1 or 2, wherein the plastics material has a melt flow index in the range 3.5 to 5.0 (ASTM).

4. A method as claimed in any one of the preceding claims wherein said chopping step comprises shredding said containers containing said coating material.

5. A method as claimed in any one of the preceding claims, wherein said container com- prises 10% to 15% by weight polyethylene, 104 to 15% by weight propylene-ethylene copolymer and 70% to 80% by weight polylzr pylene, and the total weight of said containci comprises 1.7% by weight of the coating material contained thereby.

6. A method of producing an asphalt has coating material as claimed in Claim 1 and substantially as hereinbefore described.

7. Asphalt base coating material when pl duced by the method of any one of the preceding Claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. Tensile Flexural Props Compressive Crack Strength (p.s.i,) Props (p.s.i.) Time (p.s.i.) Strength Modulus Yield Ultimate Sec Standard Asphalt Coating* Material 140 233 35911 135 168 91 Asphalt Coating* Material with Container Plastic* 192 287 39489 217 258 78 * according to the preferred embodiment of the invention Generally, utilizing a mixing tank of 2 tons capacity, the mixing time should be no less than about 45 minutes. Under normal conditions, a maximum melt time is one hour. It is thought that the presence of the aggregate filler material in the asphalt has a shearing action on the plastic and is the reason why the container material may be readily amalgamated into the asphalt. It has also been found that the presence of the container material in the coating material increases some of the physical properties of the final pipe coating. Above is a comparative analysis showing cured coating material without the container material present and with the presence of 1.7% container material. From the foregoing, it is apparent that the present invention provides for a substantially improved container for asphalt base pipe coating material and with an improved pipe coating resulting from amalgamation of the container into the coating material. Reference is made to co-pending Divisional Application No. 26731/78 (Serial No. 1580872) which describes and claims the above container, and this divisional specifically claims a coating material package comprising a rigid container housing an asphalt base corrosion protective pipe coating, said coating comprising 10% to 25% by weight asphalt and 75% to 90% by weight aggregate, said container presenting a rigid configuration comprising sidewalls and a bottom; said container comprising no more than 5% by weight of the coating material contained therein, said container being constructed from a material comprising at least one of the members of the group consisting of polyethylene, polypropylene and ethylencpropylene copolymer. WHAT WE CLAIM IS:

1. A method of providing coating material for application to a surface, said method comprising the steps of providing a plurality of individual containers filled with a coating material in solid form and including asphalt, each of which containers *as a weight of no more than 5% by weight of the coating material contained therein, and each of the said contain ers consists essentially of at least one plastics material selected from polyethylene, polypropylene, and ethylene-propylene copolymer; chopping up said containers containing said coating material to produce a mixture of particles of said container and said coating material; raising the temperature of said mixture to melt said container particles and said asphalt and produce a flowable liquid; and stirring the liquid to distribute the melted container particles homogeneously throughout the melted asphalt.

2. A method as claimed in Claim 1, wherein said temperature raising step raises said temperature to 3000 to 4000 F.

3. A method as claimed in Claim 1 or 2, wherein the plastics material has a melt flow index in the range 3.5 to 5.0 (ASTM).

4. A method as claimed in any one of the preceding claims wherein said chopping step comprises shredding said containers containing said coating material.

5. A method as claimed in any one of the preceding claims, wherein said container com- prises 10% to 15% by weight polyethylene, 104 to 15% by weight propylene-ethylene copolymer and 70% to 80% by weight polylzr pylene, and the total weight of said containci comprises 1.7% by weight of the coating material contained thereby.

6. A method of producing an asphalt has coating material as claimed in Claim 1 and substantially as hereinbefore described.

7. Asphalt base coating material when pl duced by the method of any one of the preceding Claims.