WO2017129529A1

WO2017129529A1 - Modified reactive resin compositions and use thereof for coating propping agents

Info

Publication number: WO2017129529A1
Application number: PCT/EP2017/051337
Authority: WO
Inventors: Sebastian Knör; Daniel Calimente; Arndt Schlosser
Original assignee: Wacker Chemie Ag
Priority date: 2016-01-28
Filing date: 2017-01-23
Publication date: 2017-08-03

Abstract

The invention relates to modified reactive resin compositions and the use thereof as coating agents for proppants used in hydraulic fracturing (fracking).

Description

Modified reactive resin compositions and their use for coating proppants

The present invention relates to modified

Reactive resin compositions, and their use as

Coating agent for support materials which are used in so-called hydraulic fracturing (= fracking). The fracking process is used in the extraction of oil and gas and is a method for the generation, widening and stabilization of cracks in the rock of a deposit in the deep underground, with the aim of increasing the permeability of

Increase Deposit Rocks. This can help in that

located gases and liquids easier and more resistant to flow and recovered.

The cracks generated must be kept open with proppants. The currently available, coated or

uncoated proppants are brittle and do not have the necessary compressive strength for conveying at great depths. The breakage of the proppant under the high pressure fines are released, which clog the cracks and the oil or

Reduce gas flow.

The coated available according to the state of the art

Supporting agents have improved resistance compared to the uncoated proppants. The effect of the coating, e.g. with organic resins, but is limited by the fact that the available coatings themselves are very brittle and also tend to break or flake.

State of the art

WO2008088449 A2 discloses a possibility for reducing the brittleness of coatings of such particles, wherein thermosetting reactive resins such as epoxy resins with block copolymers and coupling agents are added so as to achieve an improvement in the impact resistance of the coating. A disadvantage, in addition to the use of two additives, that the toughener is also an expensive and expensive to produce block polymers.

US2012088699A proposes particles with at least two

To coat oleophilic and hydrophobic resins, for example, epoxy resins and silicone resins. The coated particles improve the oil yield and reduce the amount

pumped water. The use of silicone resins makes these particles expensive. US8852682B2 discloses particles for use as

Supporting materials that form a multi-layered one another

have nested coating. A filler is added explicitly during the individual process steps.

A disadvantage is the complicated process. For coating various resins such as phenolic resins are used, for example, as reinforcing fillers

containing fumed silicas.

US5422183A discloses particles for use as support materials in fracking processes, which also has a two-layered structure

Have coating of resins. For example, phenolic resins are used for coating, fumed silicas being likewise used as filler. This is after the first coating step in the intermediate phase of

Single layers introduced. A disadvantage of both writings is the very complex, multi-stage process that is expensive and also difficult to control

US20140124200A discloses the use of hybrid materials made by chemically combining organic resins and silicone resins for coating support materials.

The disadvantage here is the use of expensive silicone resins, an additional, complex process for chemical modification and difficult to control product quality in the reaction of two branched polymers.

Furthermore, the prior art methods are general

known to help reduce the brittleness of

Coatings that use a reaction resin, which in itself already have a relatively low brittleness, for example, epoxy resins. W02010060861A1 describes, for example, a homogeneous reaction resin that a

Improvement of mechanical properties shows fracture toughness and impact resistance as cured thermoset plastic. This is for example in an uncured

Epoxy resin at least one organopolysiloxane homogeneously distributed by means of a silicone organocopolymer which as

Dispersant serves. Similarly, Könczöl L. et al. (KONCZOl L. et al; ISSN: 2021-8995;

10.1002 / APP.1994.070540612) the use of polysiloxane-polycaprolactone block copolymers for toughening of

Epoxy resins.

However, the prior art teaches that this extrinsic toughening modification only works if the reactive resin as such has some intrinsic toughness, as is the case with epoxy resins. For very brittle, glassy reactive resins, this method is not suitable.

(Li Zhongatao, Doctoral thesis as of 2000, entitled: "High fracture toughness and high-modulus silicone resins" published at http: // hdl. Handle. Net / 1721.1 / 8301).

Object of the invention

The object of the present invention was therefore to provide a suitable method for toughening the very brittle phenolic and melamine reactive resins and providing them of cost-effective coating compositions for proppants, a process for coating proppant and the

coated proppant. These proppants should after coating and curing the necessary hardness and

Have pressure resistance and elastic at the same time

Show properties so that it does not break or break

Spalling of the coating comes.

Solution of the task

This task is surprisingly solved by the

Modified reactive resin compositions according to the invention.

The reactive resin compositions according to the invention comprise (A) 80-99.8% by weight of at least one reactive resin

selected from phenolic or melamine resins, and

- (B) 0.2-20% by weight of at least one linear or cyclic compound

Organopolysiloxane, with the proviso that

(B) has at least 3 consecutive Si-O units

(B) at least one Si-C linked,

side chain or terminal organic radical R ¹ , wherein

^■ R ^{1 contains} at least 4 atoms selected from the group of C, N, P, O and S, and in R ¹ at least 2 of these atoms must be C, and

in (B) the ratio of the sum of all C atoms to the sum of all Si atoms is at least 2.05, and

(B) is in flowable form at 20 ° C, or by heating in a temperature range up to 250 ° C

is meltable and can be brought into a flowable form. Preferably, therefore, the critical stress intensity factor is the Klc value of the invention

Reactive resin composition at least 0.55 MN / m ^{3 2} ,

preferably at least 0.6 MN / m ^{3 2} , more preferably at least 0.75 MN / m ^3/2 .

The Klc value was determined according to ASTM D 5045 on compact tensile bodies (CT test specimens) with W = 35 mm and a

Withdrawal speed of 1 mm / min. The 4.5 mm thick CT specimens were made by CNC milling and a 3 mm cut was made with a blade.

The Tg (= glass transition temperature) of the invention

Reactive resin composition is preferably in the range 0 ° C to 250 ° C, preferably in the range 50 ° C to 230 ° C, more preferably in the range 80 ° C to 180 ° C.

The Tg is determined by means of DMTA (= Dynamic Mechanical Thermal Analysis) in torsion. The value Tg is defined here as the maximum of tan delta.

Measuring conditions:

- Measuring device: ARES Rheometer (TA-Instruments)

- Temperature range: 25 ° C - 360 ° C

- Heating rate: 4 K / min

- Frequency: 1 Hz

Samples were measured with the following dimensions: width: about 6 mm, thickness: about 3 mm, length: about 40 mm (resulting

Clamping length: approx. 27 mm). Component (A)

Preferably, the inventive

Reactive resin composition only a reactive resin (A).

The reactive resins (A) must have a solid non-sticky

Form coating at ambient temperatures. This is necessary so that the coated particles remain free-flowing, so that they do not agglomerate under normal storage conditions. The coating can be essentially

be cured so that little or no cross-linking occurs under the influence of conditions in the borehole. The

Coating can also be only partially cured or provided with other reactive groups, so that a

covalent crosslinking under the conditions downhole. Suitable reaction resins (A) according to the invention are all phenolic and melamine resins which are provided with a sufficient number of suitable reactive groups for a curing reaction.

It is crosslinking via polycondensation

Reaction resins (A) which preferably condensation products of aldehydes, e.g. Formaldehyde, with melamine, or with phenol. Curing is usually carried out by increasing the temperature with elimination of water. Not only the abovementioned reaction resins (A), but also all others which are suitable for the production of thermosetting plastics, can be modified in the manner proposed according to the invention and can be obtained according to

Crosslinking and Hardening Thermosets with significantly improved resistance to breakage and impact, with other essential properties characteristic of the thermosets, such as strength, heat resistance and chemical resistance, in the

Maintained essentially unaffected. The preferred reactive resins (A) are the phenol-formaldehyde resins. These reactive resins (A) include thermosetting ones

Resole type phenolic resins and phenolic novolac resins which can be rendered heat reactive by the addition of catalyst and formaldehyde. The reactive resins (A) can either be completely cured during the coating of the proppant particles be cured or only partially cured. Supporting agents with only partially hardened coating harden only after the

Introduction into deeper earth layers during fracking. Particularly preferred reactive resins (A) are phenol novolak resins. These are available for example from Plastics

Engineering Company, Sheboygan, USA, under the name Resin 14772. When such a reactive resin is used, it is necessary to add a crosslinking agent (C) to the mixture.

to cause the subsequent curing of the reactive resin. Hexamethylenetetramine is the preferred material as (C) for this function because it serves as both catalyst and formaldehyde source. (A) is used in amounts of at least 80 wt .-%, preferably of at least 88 wt .-%, particularly preferably at least 94 wt .-% and in amounts of at most 99.8 wt .-% and preferably at most 99.5 Weight%. Component (B)

Preferably, the inventive

Reactive resin composition only an organopolysiloxane (B).

(B) preferably has at least 5, more preferably at least 10, consecutive Si-O units.

The ratio of the sum of the C atoms to the sum of the Si atoms in (B) is at least 2.05, preferably at least 2.1 and more preferably at least 3 and preferably at most 40, more preferably at most 20, particularly preferably at most 10.

Linear or cyclic (B) may be slightly branched or slightly bridged by an organic radical. The average number of bridging or Branching sites per molecule is preferably -S 4, preferably -S 2, particularly preferably -S 1, very particularly preferably <1, (B) is preferably a linear organopolysiloxane. The average number of Si atoms per molecule (B) is preferably less than 1000, preferably less than 200, particularly preferably less than 100.

(B) is used in amounts of at least 0.2 wt .-% and at most 20 wt .-%. Preferably from at least 0.5 wt .-% and at most 12 wt .-% and particularly preferably of at most 6 wt. -%.

Another important property of (B) is that it is in a flowable form at 20 ° C, or is meltable by heating in a temperature range up to 250 ° C, and thereby can be made into a flowable form.

Definition for "flowable form" of (B):

100 g (B) are spread over 10 cm ² area of a sieve with the

Mesh size 1 mm distributed. Within 72 hours, the essential part of the material flows through the sieve at least 90%. The material at (B) above the sieve mesh which can be wiped off with a spatula is considered a residue which has not passed through the sieve. This residue is weighed to determine if a flowable (B) is present.

"Flowable" in connection with (A) and the

Reactive resin composition means that they are in a physical state of aggregation permitting distribution on the surface of the proppant (made flowable by preheating to 250 ° C or in one

dissolved suitable solvent). The organic radical R ¹ has at least 4 atoms, preferably at least 6 atoms, more preferably at least 7 atoms selected from the group of C, N, P, O and S, and of which at least 2 of these atoms are C, are preferred at least 3 of these atoms are C.

Examples of non-substituted radicals R ¹ are alkyl radicals, such as n-butyl, iso-butyl, tert. Butyl, n-pentyl, iso-pentyl, neo-pentyl, tert. Pentyl radical, hexyl radicals, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2,2,4-trimethylpentyl radical, nonyl radicals, such as the n-nonyl radical,

Decyl radicals, such as the n-decyl radical, dodecyl radicals, such as the n-dodecyl radical, octadecyl radicals, such as the n-octadecyl radical;

Alkenyl radicals, cycloalkyl radicals such as cyclopentyl, cyclohexyl, cycloheptyl radicals and methylcyclohexyl radicals; Aryl radicals, such as the phenyl-naphthyl and anthryl and phenanthryl radicals;

Alkaryl radicals, such as o-, m-, p-tolyl, xylyl and

Ethylphenyl radicals; Aralkyl radicals, such as the benzyl radical, the alpha- and the ß-phenylethyl radical.

Preferably non-substituted R ¹ are the following radicals phenyl, a-phenylethyl, n-octyl, n-dodecyl, n-hexadecyl, n-octadecyl. Examples of substituted radicals R ¹ are haloalkyl radicals, such as the perfluorohexylethyl radical; Haloaryl radicals, such as the o-, m- and p-chlorophenyl radical, and all unsubstituted radicals R ¹ mentioned above which are substituted by the following groups: mercapto groups, epoxy-functional groups,

Carboxy groups, keto groups, enamine groups, amino groups,

Aminoethylamino groups, iso-cyanato groups, aryloxy groups, acryloxy groups, methacryloxy groups, hydroxy groups and

Halogen groups.

Preferred for a substituted R ¹ is the 10-carboxydecyl radical. Further examples of substituted radicals R are short

Alkyl radicals, such as the methyl, ethyl, n-propyl, iso-propyl, and alkenyl radicals, such as the vinyl and the allyl radical, preferably with mercapto groups, epoxy-functional groups, carboxy groups, keto groups, enamine groups, amino groups, Aminoethylaminogruppen, iso Cyanato groups, aryloxy groups, acryloxy groups, methacryloxy groups, hydroxy groups and

Halogen groups may be substituted, with the proviso that the substituted radicals R ^{1 contains} at least 4 atoms selected from the group of C, N, P, 0 and S, wherein at least two C atoms must be included.

Preferred substituted radicals R ¹ are hydroxypropyl and mercaptopropyl.

Further preferred substituted radicals R are epoxy radicals of

formula

0

/ \

R ³ ₂ C - CR ³ - (R ² ) z - (VI)

or

0

/ \

R ³ C - CR ³ (VII)

in which

R ^{2 is} a divalent hydrocarbon radical having 1 to 10

Carbon atoms per remainder is by one

Ether oxygen atom may be interrupted,

R ^{3 is} a hydrogen atom or a monovalent one

Hydrocarbon radical having 1 to 10 carbon atoms per radical which may be interrupted by an ether oxygen atom, R ^{4 is} a trivalent hydrocarbon radical having 3 to 12

Carbon atoms per radical is and

z is 0 or 1. Examples of such radicals R ¹ are

Glycidoxypropyl,

3,4-epoxycyclohexylethyl,

2- (3,4-epoxy-4-methylcyclohexyl) -2-methylethyl,

3, 4-epoxybutyl,

5, 6-epoxyhexyl,

7, 8-epoxydecyl,

11, 12-epoxydodecyl and

13, 14-epoxytetradecyl-rest. Preferred epoxy radicals are the glycidoxypropyl radical and the 3,4-epoxycyclohexylethyl radical.

Further preferred substituted radicals R ¹ are amino radicals of the general formula

R ⁶ - [NR ⁷ -R ⁸ -] _n NR ⁷ ₂ (VIII), where R ^{6 is} a bivalent linear or branched

Hydrocarbon radical having 3 to 18 carbon atoms,

preferably an alkylene radical having 3 to 10 carbon atoms,

R ^{7 is} a hydrogen atom, an alkyl radical having 1 to 8

Carbon atoms or an acyl radical such as acetyl radical, preferably a hydrogen atom,

R ^{8 is} a divalent hydrocarbon radical having 1 to 6

Carbon atoms, preferably an alkylene radical having 1 to 6 carbon atoms,

n is 0, 1, 2, 3 or 4, preferably 0 or 1. Further preferred substituted radicals R are polyether radicals of the general formula

-CH ₂ CH ₂ (CH ₂ ) _u O (C ₂ H ₄ O) _v (C ₃ H ₆ O) _w (C ₄ H ₈ O) _x R ⁹ (IX) where

R ⁹ denotes a hydrocarbon radical having 1 to 6 carbon atoms or H, preferably Me or H,

u is 0 or an integer from 1 to 16, preferably 1 to 4,

v is 0 or an integer from 1 to 35, preferably 1 to 25, and

w is 0 or an integer from 1 to 35, preferably 1 to 25,

x is 0 or an integer from 1 to 35, preferably 1 to 25

with the proviso that the sum of v + w + x is 1 to 70, preferably 1 to 50.

Further preferred substituted radicals R ¹ are organic polymer radicals with formation of a polysiloxane-containing copolymer. These copolymers may be block or graft copolymers. Examples of suitable organic parts include, but are not limited to, polycaprolactone, polyesters, polyvinyl acetates, polystyrenes, polymethyl methacrylates.

The organic part is preferably a (co) polymer

Vinyl acetate, methyl methacrylate or aliphatic polyester. Particularly preferred is polycaprolactone.

The block copolymers contain a siloxane unit having a molecular weight of 1,000-10,000 g / mol, preferably 1,500-5,000 g / mol, more preferably 2,000-4,000 g / mol.

Particularly preferred radicals R are polyether radicals, epoxy particularly preferably the glycidoxypropyl radical and the 3,4- Epoxycyclohexylethyl radical, and organic polymer radicals, particularly preferably a polycaprolactone radical.

Another object of the present invention is the

Process for the preparation of the reactive resin composition.

This is done in one embodiment by dispersing (B) in (A) which is flowable at 20 ° C. or in (A) which has been made flowable by prior heating to 250 ° C. or in (A) which has been dissolved in a suitable solvent has been. The person skilled in the art is aware of the way in which (A) can be converted into flowable form without initiating the hardening. If a solvent has been used, this can be evaporated afterwards. Suitable solvents are known to the person skilled in the art and are selected as a function of the reactive resin (A). For phenolic resin, suitable solvents are, for example

Ethyl acetate and acetone. Which solvents for which

Reactive resins are suitable, is described for example in the following textbook: Polymer Handbook. Volume 2, 4 Ed .; J. Brandrup, E.H. Immergut, E.A. Grulke; John Wiley & Sons, Inc., 1999 (ISBN 0-471-48172-6).

Suitable mixers are, for example, laboratory stirrers,

Plant mixer, or dissolver, or rotor-stator systems, or even extruders, rollers, 3-roller chair, etc. (B) can dissolve when dispersed in whole or in part in (A). Undissolved components are present as the second phase in (A) dispersed. The mean size of these domains is

preferably less than 50 μιη, preferably less than 20 μιη, more preferably less than 10 μιη, most preferably less than 1 μτ.

Another object of the present invention is the

Use of the reactive resin composition according to the invention for

Coatings and for the production of molded parts, workpieces and foams. In particular, the inventive Reactive resin composition used for coating proppants.

Another object of the present invention is the

Process for the preparation of proppants coated according to the invention.

Various possibilities for coating proppants with resins from the prior art are known to the person skilled in the art.

These methods can also be used for the coating of

Supporting agents with the present invention

Reactive resin compositions are used.

In order to make maximum use of the advantageous effect of the coating, it is important to have a particularly good dispersion of (A) with

(B) to ensure. In the preferred embodiment, the reactive resin composition according to the invention in

flowable form - ie already at 20 ° C flowable or melted by heating to 250 ° C and therefore flowable or dissolved in a suitable solvent and therefore flowable together with or without at least one curing agent (C) and with or without at least one additive (D. ), on the proppant

applied, for example by spraying or mixing and then cured.

In a particularly preferred embodiment, the

inventive reactive resin composition melted by heating to 250 ° C and therefore flowable together with or without at least one curing agent (C) and with or without at least one additive (D), applied to the proppant

for example, by spraying or mixing and then cured.

For solvents, the above applies. On the other hand, if economic advantages are more important or if maximum flexibility is advantageous in the production process of the coated proppants, then the following alternative production process is used. One can use the first part-step also as in-situ procedure for the production of the

The reactive resin composition according to the invention, since it takes place in the presence of the proppant. In this

Preparation process (B) together with at 20 ° C flowable (A) or with (A) which was made by prior heating to 250 ° C flowable or with (A) which was dissolved in a suitable solvent and the proppant and optional addition of hardener (C) and optionally further additives (D) mixed and hardened. The order of addition of the components (A), (B), (C) and (D) is variable, with the proviso that the component (B) is mixed before a substantial hardening of the reactive resin occurs. This has the advantage that a short-term adaptation of the ratios of (A) to (B) in a simple and straightforward way can be done at any time.

This process for the production of coated

Supporting means, is thus characterized in that

i) an in situ preparation of the reactive resin composition by mixing at least one (B) with at least one flowable at 20 ° C (A) or with (A) which was made by prior heating to 250 ° C flowable or with (A ) which has been dissolved in a suitable solvent and at least one proppant and with or without at least one curing agent (C) and with or without at least one additive (D), and

ii) curing only then.

In a further alternative production method for

According coated according to the invention support (A) with a suitable solvent, proppant and (B). Of the

Mixture can optionally hardener (C) and possibly different Additives (D) are added. Subsequently, the solvent is evaporated off and the so coated adhesives are cured. The order of addition of components (A), (B), (C) and (D) is variable.

In a particularly preferred possible embodiment, a suitable proppant such as sand is preheated to about 170-260 ° C. In a mixer is then the

Reactive resin composition according to the invention, a suitable hardener (C) and optionally various additives (D) are added.

In another alternative, a suitable proppant such as sand is preheated to about 170-260 ° C. In a mixer, then (A), (B), a suitable hardener (C) and optionally various additives (D) are added.

The generation of layers is to be understood as follows:

Multiple layers are produced in several consecutive coating and curing cycles. That is, after wetting the surface of the proppant with the

Reactive resin composition according to the invention, this layer is first partially or completely cured.

Subsequently, a new layer of the invention

Reactive resin composition applied and partially or fully cured again.

This contrasts with the application of the invention

Reactive resin composition in portions in several steps without substantial intermediate curing of the individual portions and only at the end of a partial or complete curing. This therefore only leads to a single layer.

proppant

Suitable proppants are known to those skilled in the art for a long time and can for the inventive Coating be used. Supporting agents are usually hard, high-strength particles such as sand or gravel from rocks such as limestone, marble, dolomite, granite, etc., but also glass beads, ceramic particles, ceramic balls and

the like, this list being exemplary and not

is restrictive. Preferably, the proppant particles have a substantially spherical or spherical shape, since they leave enough space for the crude oil or gas

can flow past. Therefore, coarse-grained sand, glass beads and glass bubbles (so-called microballoons) are preferred as the proppant. Sand is particularly preferably used as a proppant.

Preferably, the proppant particles have an average size of 5,000 to 50 μm, more preferably one

average size of 1,500 to 100 μη. In addition, they preferably show an aspect ratio of length to width of

at most 2: 1.

Hardener (C)

Suitable hardeners are known to those skilled in the art for a long time and are according to the

used reactive resin selected. A preferred novolak curing agent (C) is urotropin. (C) and thus also urotropin is typically used in amounts of between 8 and 20% by weight, based on the amount of reactive resin composition according to the invention. Preferably, urotopin is applied as an aqueous solution to the melt of the reactive resin. Such methods are also known to those skilled in the art and described for example in US4732920.

Additive (D)

Suitable additives (D) have also long been known to the person skilled in the art. Non-exhaustive examples are anti-static agents, release agents, adhesion promoters, etc. Suitable proppants, hardeners (C) and additives (D) are described for example in US4732920 and US2007 / 0036977 AI. For optimum performance of the proppants coated according to the invention, the type and specification of the proppant, type and specification of the reactive resin (A), organopolysiloxane (B), hardener (C) and optionally additives (D), the type of mixing and coating process must Order of addition of the

Components and the mixing times are coordinated according to the requirements of the specific application. A change in the proppant may require an adjustment of the coating process and / or the hardener used (C) and additives (D).

A further subject thus also according to the invention obtainable according to the methods described above

coated proppant. In the case of the proppants according to the invention, the surface of the proppant may be completely or partially coated. Preferably appear in the investigation with the

Scanning electron microscope at least 20% of the visible

Surface of the proppant with the inventive

Reactive resin composition coated, more preferably at least 50%.

Preferably appear in the investigation with the

Scanning electron microscope at least 5% of the proppant particles completely enveloped on its visible side, more preferably at least 10%.

The essential part of the coating on the proppant according to the invention is 0.1 to 100 μιη thick, preferably 0.1 to 30 μιτι, more preferably 1 to 20 μη. Preference is given to the proppants of the invention having less than three layers of the invention

Reactive resin composition coated. Particularly preferred with only one layer.

The reactive resin composition according to the invention is preferably used in amounts of 0.1-20% by weight, based on the weight of the

Supporting agent used. Preferably from 0.5-10% by weight and more preferably from 1-5% by weight.

Another object of the present invention is the

Use of the proppants coated according to the invention in fracking production processes for crude oil and natural gas.

Advantages of the invention

The reactive resin composition according to the invention has

improved flow properties in coating processes. This will coat surfaces more evenly. Smoother and glossier surfaces can be obtained.

The novel reactive resin compositions show

Advantages in coating of proppant, in that the waste is significantly reduced by bonding the proppant.

The cured reactive resin composition of the present invention has improved toughness, elasticity and ductility at the same hardness. This makes it more resistant

against loads such as impacts, deformation or pressure and has a lower tendency to break.

The reactive resin composition of the present invention has improved as a hardened coating for proppant

Breaking strength, toughness and elasticity. The Coating has a reduced tendency to break and

Chipping and protecting the proppant more effectively and permanently against high pressures and shocks. Thus, the durability of the entire proppant improves.

Conventional support means according to the prior art are very brittle and have a great tendency to break. Breakage of the proppant will release fines. A

Release of the fines has a negative effect on the

Flow rate of the crude oil or gas, characterized in that the gaps between the proppant grains are clogged. This quickly makes the oil or gas source unprofitable. New drilling or refracking will be required.

In contrast, the coated according to the invention

Supporting agent more resistant to stress, such as

Impact, deformation or pressure and thus have a lower tendency to break.

Another advantage of the coating according to the invention lies in its deformability, so that it often does not break even when breaking the brittle proppant grains themselves and thus encloses or holds together the resulting fines such as a plastic shell and thus their total release

is reduced.

Due to these advantageous properties of the proppants coated according to the invention, the oil or gas flow can be maintained longer. This results in decisive economic benefits and environmental protection.

Examples

The following examples illustrate the invention without being limiting. In the following

Examples refer to all parts and parts Percentages, unless otherwise stated, by weight. Unless otherwise stated, the following are

Examples at a pressure of the surrounding atmosphere, that is about at lOOOhPa, and at room temperature, ie at 25 ° C, or at a temperature that occurs when combining the reactants at room temperature without additional heating or cooling carried out. In the following all relate

Viscosity data to a temperature of 25 ° C.

used abbreviations

The meaning of the abbreviations used above also applies to the examples:

PTFE = polytetrafluoroethylene

Rpm = revolutions per minute

example 1

A glass flask was purged with nitrogen, filled with 475 g of Novolak "Resin 14772" (Plastics Engineering Company, Sheboygan, USA) and purged with nitrogen again, the mass was melted at 120 ° C. Then, a stirrer was switched on at 420 rpm g WACKER®WAX OH 350 D-RO (a linear

Polysiloxane-polycaprolactone block copolymer of melting point 50 ° C and about 30-50 Si-O units) were added and stirred at 420 rpm for 10 minutes. The liquid mass is poured hot onto a PTFE film and mechanically comminuted, thus producing a granulate.

Example 2

Following the procedure of Example 1, 25 g of SIPELL® RE 63 F (a polydimethylsiloxane having glycidoxypropylmethylsiloxy units and about 100-160 Si-O units;

dynamically at 25 ° C approx. 300 mPa.s; ) instead of WACKER®WAX OH 350 D-RO (available from Wacker Chemie AG, Munich) incorporated and produced a granulate.

Example 3

Following the procedure of Example 1, 25 g of silicone oil 1 (a trimethylsiloxy-endstopped polydimethylsiloxane having about 75-85 Si-O units consisting of dimethylsiloxy units and an average of 2.5 glycidoxypropylmethylsiloxy units and an average of 2.5

(Hydroxy (polyethyleneoxy) (polypropyleneoxy) propyl) methylsiloxy units per molecule; Viscosity, dynamic at 23 ° C,

Brookfield, 2300-2500 mPa.s) instead of WACKER®WAX OH 350 D-RO and granules are produced. Example 4

Following the procedure of Example 1, 25 grams of silicone oil 2 (an a, co-functional silicone oil having about 15-20 Si-O units and hydroxy (polyethyleneoxy) end groups of about 10

Repeating ethylene oxide units; Viscosity, dynamic at 25 ° C, Brookfield, 150-300 mPa.s), instead of WACKER®WAX OH 350 D-RO incorporated and produced a granulate.

Example 5

A glass flask was purged with nitrogen, with 475 g of Novolak "Resin 14772" (Plastics Engineering Company, Sheboygan,

USA) filled and rinsed again with nitrogen. The mass was melted at 120 ° C. Then a stirrer was switched on at 420 rpm. 12.5 g of WACKER® WAX OH 350 D-RO was added and stirred at 420 rpm for 5 minutes. Thereafter, 12.5 g

WACKER® AK 100 SILICONOEL, a non-functional,

Trimethylsiloxy-endstopped polydimethylsiloxane, added and stirred for a further 10 minutes. The liquid mass is poured hot onto a PTFE film and mechanically comminuted. Comparative Example 1 (VI) Following the procedure of Example 1, 25 g of WACKER® AK 100 SILICONOEL, a non-functional, trimethylsiloxy end-capped polydimethylsiloxane, was incorporated instead of WACKER® WAX OH 350 D-RO.

Unexpectedly, it turns out that the invention

Distribute organopolysiloxanes (B) uniformly and finely in the reactive resin. If a second phase is formed, this is essentially in the form of spherical droplets. The non-inventive polysiloxane from Comparative Example VI is not homogeneously dispersible and forms unevenly distributed streaks in the reactive resin.

Comparative Example (V2)

Comparative Example C2 is unmodified novolac "Resin 14772" (Plastics Engineering Company, Sheboygan, USA)

Preparation of reactive resin solutions for the production of

Test specimen and coating of Q-PANEL test sheets:

In each case, 10 parts of the modified phenolic resins according to the invention from Examples 1 to 5, or 10 parts of non-inventive, modified phenolic resin from the

Comparative Example VI or 10 parts of the pure non-inventive, unmodified phenolic resin Resin 14772 (Plastics Engineering Company, Sheboygan, USA), each containing 1 part of urotropin and 10.0 parts of ethyl acetate (Bernd Kraft,> = 99%). ) by shaking overnight.

Example 7

Preparation for test specimens for determination of Klc and Tg:

The solutions of Example 6 are 12 mm high in one

Poured aluminum mold and over 8 days from 40 ° C to 120 ° C. heated. Thereafter, each 2 h at 120 ° C, 140 ° C and 160 C ° is heated and cooled evenly overnight. This gives hard, brown, about 6 mm thick test plates. Table 1 shows the comparative data of the modified

Phenolic novolac resins.

These inventively modified resins have an im

As compared to the unmodified phenolic resin, Klc value increased (determination analogous to the above-mentioned description), which represents a measure of improved toughness. The inventively modified resins are more elastic and have a reduced Tg compared to the unmodified phenolic resin.

Example 8

Preparation of phenol resin-coated Q-PANEL test panels:

For the brittleness determination tests, Q-PANEL test panels on the brushed side were cleaned 3 times with acetone and then vented for 1 h in a fume hood. Subsequently, 3 ml of the corresponding phenolic resin solution from Example 6 were added to each plate and spread with a 100 ym knife and then the solvent was evaporated in a fume hood overnight.

For curing, the samples were placed in a cold oven, heated to 160 ° C with rinsing with nitrogen within 3 hours, kept at this temperature for 2 h and cooled to 23 ° C overnight.

After evaporation of the solvent, an approximately 50 μιη thick cured resin layer is formed on the plate.

Example 9

Resistance testing:

By means of ball impact tester, the resistance of the

Coating be considered in isolated form. One receives a statement to the elasticity, impact resistance and

Breaking strength of a coating.

To prove the improved properties, ie the toughness and resistance to shocks and pressures, was after Example 6 and 8 each about 50 μιη thick, cured

Layer of the resins of the invention from Examples 1-5 on a Q-PANEL test sheet prepared, or as

Comparative Examples, an approximately 50 μιη thick, hardened layer of the unmodified resin Resin 14772 (Plastics Engineering Company, Sheboygan, USA) and the non-inventive resin of Comparative Example VI. The coated panels were tested on an Erichsen ball impact tester, Model 304-ASTM, and the results were visually evaluated by a trained examiner: To do this, drop a ball onto the back of the panel from a defined, variable height of fall (each duplicate at different locations). The impact energy is calculated from the height of fall multiplied by

Falling weight, expressed in inches (in) x pounds (lbs). The

Impact energy is changed as follows: 5, 10, 15, 20, 25, 30, 35, 40 (in x lbs). The dentate impact sites are visually inspected for cracks and cracks and rated relative to the reference. Table 2 shows the evaluation of the resin coating on Q-PANEL test panels and their resistance by means of

Ball impact tester.

Table 2

The values are to be understood as follows:

"0" means crack image similar to the reference The reference shows already at lowest energy, from 5 in x lbs, clear cracking The extent of cracking is similar to the

Reference.

"+" Means crack image better than the reference, i.

clear cracks are only at higher energy in the area 10 - 30 in x lbs, or the extent of cracking is significantly reduced overall compared to the reference. "++" means that there are no cracks up to an energy of 30 in x lbs.

It turns out quite unexpectedly that the coatings according to the invention lead to smoother surfaces, whereas the comparative example VI not according to the invention, although containing a polysiloxane, does not

According to the invention, this very advantageous effect does not show. In addition, the cured coatings of the present invention have significantly improved resilience, impact strength, and fracture toughness compared to the unmodified

Comparative Example C2 and not according to the invention

modified Comparative Example VI on. This is completely surprising because the prior art teaches that

extrinsic impact modifiers are not suitable for the very brittle, glassy reactive resins such as phenolic resins

effectively improving (Li Zhongatao, PhD thesis as of 2000, entitled: "High fracture toughness and high modules silicone resins" published under

http://hdl.handle.net/1721.1/8301).

Example 10

Production of coated proppants:

20-40 mesh fracking sand was treated with 3.5% of the resins of Examples 1 and 5 according to the invention, or as comparative examples with 3.5% of the unmodified resin Resin 14772 (Plastics Engineering Company, Sheboygan, USA) and the non-inventive resin from Comparative Example VI in

Melt coated and cured with 10 wt .-% urotropin, based on the amount of resin. Table 3 shows the evaluation of the coating quality of

Fracking sand with modified resin from Example 1 by means of electron microscopy (SEM). Table 3

It turns out that the inventive

Reactive resin composition causes a more uniform and effective coating of the surface of the proppant.

Example 11

Investigation of the pressure stability of coated

Proppants:

The pressure stability of the coated proppant according to

Example 8 was tested according to DIN EN ISO 13503-2 at 14000 PSI and 18000 PSI pressure. The result is shown in Table 4. Table 4

Fracking sand coated amount of fine fraction formed in% with resin from example

at 14000 PSI at 18000 PSI

1 7,4 12, 1

4 8,4 15, 1

5 7.5 12.7

VI 12, 9 19, 8

V2 10.3 15, 9 It is completely surprising that in the

20-30% less fines is formed in accordance with the invention-coated proppants, compared to non-modified coated proppant. The improvement of

Pressure resistance of the coated according to the invention

Supporting agent was completely unexpected, because an improvement in the fracture and impact resistance of the invention

modified reactive resins did not allow a fundamental conclusion that this automatically leads to an improvement in the pressure resistance.

Claims

claims

1. Reactive resin composition containing

(A) 80-99.8% by weight of at least one reactive resin

selected from phenolic or melamine resins, and

(B) 0.2-20% by weight of at least one linear or cyclic organopolysiloxane, with the proviso that

- (B) at least 3 consecutive Si-O units

having

(B) at least one Si-C linked,

side chain or terminal organic radical R ¹ , wherein

■ R ^{1 contains} at least 4 atoms selected from the group consisting of C, N, P, 0 and S, and ■ in R ¹ at least 2 of these atoms are C.

need, and

is meltable and can be brought into a flowable form.

2. Reactive resin composition according to claim 1, characterized

characterized in that in (B) the ratio of the sum of all C atoms to the sum of all Si atoms is at least 2.10.

3. Reactive resin composition according to claim 1, characterized

characterized in that (B) has at least 5 consecutive Si-O units.

4. A process for producing the reactive resin composition according to claim 1 to 3, by dispersing (B) in at 20 ° C flowable (A) or in (A), which was rendered flowable by prior heating to 250 ° C or in (A) which was dissolved in a suitable solvent.

5. Use of the reactive resin composition according to

Claims 1-3 for coatings and for the production of

Moldings, workpieces and foams.

6. Use of the reactive resin composition according to

Claims 1-3 for coating proppants.

7. A process for the preparation of coated proppants, characterized in that the reactive resin composition according to one of claims 1 to 3 in flowable form, together with or without at least one curing agent (C) and with or without at least one additive (D), on the proppant

is applied and then cured.

8. A process for the preparation of coated proppants, characterized in that

i) the preparation of the reactive resin composition is carried out as an in-situ process in the presence of the proppant, wherein at least one (B) and

at least one at 20 ° C flowable (A) or with (A) which was made by prior heating to 250 ° C flowable or with (A) which was dissolved in a suitable solvent, and

at least one proppant

with or without at least one hardener (C)

with or without at least one additive (D)

to be mixed

ii) and only then the curing takes place.

9. Coated proppant obtainable from the process according to claim 7 or 8.

10. Use of the coated proppants according to claim 9 in fracking process for crude oil and natural gas.